wireless network logon

We have just configured some new laptops running Windows 7 SP1 and linked them through a normal ethernet connection to join our school Server 2008 R2 domain. They can log on to the domain with any user account. We have used them to connect wirelessly to the domain once someone has logged on with a wired connection and estblished their profile on the laptop.
The problem arises when another user tries to log on to the domain through the wireless connection. It seems to time out and not log on or establish their profile. We had this problem with Windows XP laptops and I fixed that with an alteration to the registry, which altered the period that it took for the wireless logon to time out. It was set to 30 secs and we altered it to 120 secs using the instructions in the link below.

Group Policy application fails on a computer that is running Windows 2000, Windows XP Service Pack 1, or Windows XP Service Pack 2
Group Policy application fails on a computer that is running Windows 2000, Windows XP Service Pack 1, or Windows XP Service Pack 2

Has anyone else had this issue with Win 7. Should I apply a similar fix or is it something else?
Are there Group Policies for wireless connections?

Maybe their profiles are just too large to drag over the wifi and it times out? I use allow local profile only on my clients to ensure fast login times even for new users.