[kh99]

It looks like you could almost - but not quite - use plugins to modify the user data manager to handle fields in another table. The problem seems to me to be the do_set() function (in includes/class_dm_user.php, around line 1587). There's a hook (userdata_doset) that could be used to set the table that a custom field is in, but unfortunately the code below that seems to depend on the class having a variable named the same as the table ([S]and I don't believe you can add a variable to a class via a plugin[/S] - oops, see below).

There still maybe some way to use the existing hooks to get your values saved at the same time as the existing user tables, I just don't see a way to make it work the same as the other tables.

Edit: Actually, I'm embarrassed to say that I appear to be completely wrong - it looks like you can add a variable to an object just by setting it. So, you should be able to use hook userdata_start to add your valid fields to the $validfields array, then use hook userdata_doset to add your table to the tables array if $fieldname is one of your fields. There may be other things you have to do to get it to work - I haven't actually tried it all yet.