I'm using a custom form as the default in an Exchange Server public contacts folder to force users to pick from a list of categories for each contact. If I synchronize the folder with my Palm device, save received vCard contacts to the folder, or copy new items to the folder, will they use the same custom form?
No. When you make a custom form the default form for a folder on the folder's Properties dialog box, that form applies only to items that you create with the New button or the Actions, New name of form command. Any contacts added through another method will use Outlook's default contact form.
To apply your custom form to items that use the default form, you must change the value of the MessageClass property for each item. Several free tools are available to perform this task, including the DocMessageClass utility from http://www.outlookstore.com and a Microsoft Word Visual Basic for Applications (VBA) macro described in the Microsoft article "OL2000: Word Document to Change Message Class of Outlook Items" (http://support.microsoft.com/?kbid=201089).