[kh99]

I think you can probably use the hooks in the file class_dm_user.php (and maybe class_dm.php, the base class) to add a verification function for your new field, and in that function you should be able to do your check and set another field.

I can give you more details if you want. I have some code somewhere that does something similar.

Edit: Here's a mod that shows how to add a verify function to a user field: www.vbulletin.org/forum/showthread.php?t=283540