Outlook custom form for Entourage 2008

Hi;

I have customized Outlook form (vacation request form) for Outlook 2003- Outlook 2010.  this form has published to library in Exchange already, all Windows based Outlook user has no problem to open it and read it except one user who is using Entourage 2008 on his MacBook.  I did some research and they said that the Outlook form cannot be supported by Mac, is it true?

thanks