So I have 2 questions

These are the facts that I've gathered:

UserProfile.ProfileProperties( ) is ReadOnly
UserProfile.ProfilePropertyAccess does not have a way to modify a ProfilePropertyDefinition for a given UserInfo

Ah... here's something interesting UserProfile.SetProfileProperty(String, String)

My question:

Maybe this first one is silly.  1.  Suppose we have user As UserInfo and definition As ProfilePropertyDefinition (assume they are not null)

Can I call user.ProfileProperites.Add(definition)  even though ProfileProperties is ReadOnly? 

2.  Does UserProfile.SetProfileProperty(String, String) create the property if it does not exist?   

I promise I'll write some documentation for this stuff once I figure out what's going on.

Cheers.

Perfect.   Thanks for your help.

Funny that you posted about this, I just discovered the same thing two days ago. Just for reference; 

You CAN change the Profile Properties using SetProfileProperty as such:

objUser.Profile.SetProfileProperty("propertyname", "your new value");

Then, to update the db;

ProfileController.UpdateUserProfile(objUser); 

 I just wanted to put this out there because I searched for a long time before I came up with it.