How to specify the sender's email address or reply-to email address when using PB 10 & Outlook

I have created an application that allows our users to email preformatted messages to customers concerning their orders.  We were using Outlook Express, but now, we are using MS Exchange and MS Outlook.  I cannot specify the sender's email address that should be used by everyone or the reply-to email address (if one exists).

Basically, I need the ability to will allow the different users to send an email to a customer and when the customer replies back to the email, it will go to one email address, as in orders@xxxxxxxxx.com.

I have gotten around the profile issue in that everyone has the same profile name.  But when an email is sent via the application, instead of having the orders@xxxxxxxxx.com email address in the sender's email address, it has the default email address of the user.

The code that I am using is as follows:

If lb_goodtosend = True Then

      // Create a mail session
      mSes = create mailSession

      // Log on to the session
      mRet = mSes.mailLogon("profilename", "profile password", mailNewSession!)

      IF mRet <> mailReturnSuccess! THEN
            MessageBox("Mail", 'Logon failed.')
            RETURN
      END IF

      // Populate the mailMessage structure
      mMsg.Subject = ls_subject
      mMsg.NoteText = ls_message
      li_array = 1
      mMsg.Recipient[li_array].RecipientType = mailTo!
      mMsg.Recipient[li_array].name = ls_sendto
      if ls_copyto <> "" Then
            li_array++
            mMsg.Recipient[li_array].RecipientType = mailcc!
            mMsg.Recipient[li_array].name = ls_copyto
      End If

      // Send the mail
      mRet = mSes.mailSend(mMsg)

      IF mRet <> mailReturnSuccess! THEN
            MessageBox("Mail Send", 'Mail not sent')
            RETURN
      END IF

      mSes.mailLogoff()

      DESTROY mSes
End If

Thanks in advance!

Keith Roberts