V-Cards with Exchange Server

We do not maintain full information in AD.
When you create a Contact entry for yourself with full information, you can insert this as a V-Card into a mail message.
However, when you try to add the V-Card to your Signature the field information from AD overrides the contact folder information.
One solution would be to give users update to their personal information in AD, but that is most unlikely to happen.
Is this a site specific or general problem? Any other solutions?