Because Core Messaging Module doesn't support HTML I need to create my own module based on DotNetNuke.Services.Social.Messaging.MessagingController and DotNetNuke.Services.Social.Messaging.Message.

The only problem I have is how to replay to a message?

In the table dbo.CoreMessaging_Messages there is a field ConversationId that keep a Message ID from the original message. 

Let say original message has MessageID #123. I need to replay to this message and I'm expecting that ConversationId will have this 123.

It works if I open a message Core Messaging Module page and click replay. But I'm not able to do it programmatically.

I login as user 1, creating a message. Now both MessageID and ConversationId have the same value 123.

I'm login from another browser under user 2 user name, creating a message and assign a value to the property .DotNetNuke.Services.Social.Messaging.Message.ConversationId the same value 123.

It doesn't work. Message created by ConversationId has a different value (for example 124).

In both original and replay message subject hasn't chnaged

Here is my code.

  Private Sub SendSocialMessage()

        Dim Mymessage As New DotNetNuke.Services.Social.Messaging.Message

        Dim mc As New DotNetNuke.Services.Social.Messaging.MessagingController

        Dim oUser As New UserInfo

        Dim oSender As New UserInfo

        Dim _PortalSettings As PortalSettings = PortalController.Instance.GetCurrentPortalSettings

        Dim UserList As New List(Of UserInfo)

        Try

            oSender = _PortalSettings.UserInfo

            Dim rec As String = ""

            If oSender.Username = "user1" Then

                rec = "user2"

            Else

                rec = "user1"

            End If

            oUser = UserController.GetUserByName(0, rec)

            UserList.Add(oUser)

            With Mymessage

                .Body = "Some Body Text"

                .Subject = "some subject text"

                .From = oSender.Username

                .SenderUserID = oSender.UserID

                .To = oUser.Username

                .ConversationId = 123

                .MessageID = 123

                .KeyID = 123

                .ReplyAllAllowed = True

            End With

            mc.SendMessage(Mymessage, Nothing, UserList, Nothing, oSender)

            Response.Write("Ok")

        Catch ex As Exception

            Functions.SaveError(ex)

            Response.Write(ex.Message)

        End Try

    End Sub

Thanks.