Dialup connections disappers after joining domain

Hi,
We are having problems with our laptops. When we creat dialup connections to dial in to our server they all work OK but once we join same laptops to our domain all dialup connections disappear even we login to the local account with same user which has admin rights.
We try to crate new connection but dial up connection box is grayed out
Any help will appreciated
Thanks

Wajhi