This is an older post but I figured for all the solutions I've been given I'd give back.

 For our application, we have junior sales reps who we want to be able to create child portals for clients without being in a Super User role.  However, we don't want them to have admin control, just their bosses get this.  So the sequence is, create the portal, get the UserID of the Sales Rep's boss, make them the admin and in the Create Portal routine we make that senior user the user admin.

All well and good but now the Sales Rep needs access too!  No problem, he's the logged in user so we do this:

if(UserInfo.IsInRole("Sales Rep"))
                            {
                                UserInfo salesRep = new UserInfo(); <-- Note: DotNetNuke UserInfo is same case as ...
                                salesRep.FirstName = UserInfo.FirstName; <-- PortalModuleBase UserInfo ... different critters, same name !!! -- No context sensitive highlighting here makes this a bit hard to absorb.
                                salesRep.LastName = UserInfo.LastName;
                                salesRep.DisplayName = UserInfo.DisplayName;
                                salesRep.Email = UserInfo.Email;
                                salesRep.PortalID = intPortalId;
                                salesRep.Membership.Password = UserInfo.Membership.Password;
                                salesRep.Membership.PasswordConfirm = UserInfo.Membership.Password;
                                if (UserController.CreateUser(ref salesRep) == UserCreateStatus.Success)
                                {
                                    RoleController rc = new RoleController();
                                    RoleInfo ri = rc.GetRoleByName(intPortalId, "RegisteredUsers");
                                    rc.AddUserRole(intPortalId, salesRep.UserID, ri.RoleID, Null.NullDate);
                                }                            
                            }

Testing for the Sales Rep role, when I'm logged in as Host or Admin and test other code, this is not fired.  What I'm looking up now is how  to just create the role of Sales Rep in the child portal and then add the currently logged in sales rep to it, etc.  I don't see the method right now but it should be straightforward.

If anyone needs the code to do a similar action I'll share it.  Piecing it together from the different forum posts is very easy however.  I'm quite thankful I'm not the first person down this path. :)

As promised, here is the code for adding in users to child portals. I'm showing the entire part of the method I'm working with, which will make things clearer.

A note here -- the only reason a user won't be added to a child portal is required fields in the User Info, Membership or Profile not being correct or a NULL is getting added. The most common case of this is getting the password for the User without using methods in the Membership Property of the User Info. I'll include this as well.

BTW, whoever had the patience to do this with the stored procedure is a very meticulous person. I prefer the lazy way, myself ... :)

Here is the code:

//Create Portal
if (String.IsNullOrEmpty(message))
{
//Attempt to create the portal
UserInfo adminMasterRep = new UserInfo();
int intPortalId;
/*
* Set up the site so that any Master Sales Rep created / deleted is automatically added/removed from the Master
* Sales Rep -- Sales Rep table. There should just be a text box and an Update button for the Super User page in the
* site to list out who is deleted, who is added.
*/

try
{
adminMasterRep = new UserInfo
{
FirstName = masterRepInfo.FirstName,
LastName = masterRepInfo.LastName,
Username = masterRepInfo.Username,
DisplayName = masterRepInfo.FirstName + " " + masterRepInfo.LastName,
Email = masterRepInfo.Email,
IsSuperUser = false,
Membership =
{
Approved = true,
Password = masterRepAdminUser.GetPassword(),
PasswordConfirm = masterRepAdminUser.GetPassword(),
PasswordQuestion = masterRepInfo.Membership.PasswordQuestion,
PasswordAnswer = masterRepInfo.Membership.PasswordAnswer
},
Profile =
{
FirstName = masterRepInfo.Profile.FirstName,
LastName = masterRepInfo.Profile.LastName
}
};

intPortalId = objPortalController.CreatePortal(txtPortalName.Text,
adminMasterRep,
txtDescription.Text,
txtKeyWords.Text,
template,
homeDir,
strPortalAlias,
strServerPath,
strChildPath,
blnChild);

//Add the sales rep as a registered user for the new portal
if (UserInfo.IsInRole("Sales Reps"))
{
UserInfo salesRep = new UserInfo
{
FirstName = UserInfo.FirstName,
LastName = UserInfo.LastName,
DisplayName = UserInfo.DisplayName,
Email = UserInfo.Email,
PortalID = intPortalId,
IsSuperUser = false,
Membership =
{
// Further up in the code above this part of the method lives this:
//Creating object of MembershipUser class which will take username as parameter.
//This is the only way to get the password for the admin user.
// MembershipUser masterRepAdminUser = Membership.GetUser(masterRepInfo.Username);
// gets the password for the Sales Rep's boss ...
// MembershipUser loggedInSalesRep = Membership.GetUser(UserInfo.Username);
// gets the password info for the logged in rep, as below.
Username = UserInfo.Username,
Password = loggedInSalesRep.GetPassword(),
PasswordConfirm = loggedInSalesRep.GetPassword()
},
Profile =
{
FirstName = UserInfo.Profile.FirstName,
LastName = UserInfo.Profile.LastName,
Cell = UserInfo.Profile.Cell,
Telephone = UserInfo.Profile.Telephone,
IM = UserInfo.Profile.IM
}
};

UserController.CreateUser(ref salesRep);

if (salesRep.UserID > 0)
{
RoleController rc = new RoleController();
RoleInfo ri = rc.GetRoleByName(intPortalId, "Registered Users");
rc.AddUserRole(intPortalId, salesRep.UserID, ri.RoleID, DateTime.Now.AddDays(365));
}
}