Windows lock and unlock ambiguity

Hi,

At work i have a windows 7 based pc that is joined to a domain. Now what happens is this:

1. I login to the office domain.

2. I lock my pc

Now when i press ctrl+alt+del to unlock the pc it presents me with local pc user login. So i have to press switch user, click on the current logged in domain account and enter pasword to unlock. This happens every time when i lock my domain account. Is this the way that unlocking in Win 7, joined to a domain, works? In XP when i pressed ctrl+alt+del to unlock pc i just had to enter the pwd.

Can you give me a solution to this problem.:confused:

Thanx
Anupam