Install .ipa-files

Hi,

I'm pretty new on iPad2, so I have a question about installing applications.

How do you do this? I have this .ipa-file from my company. It's a beta application, and it's not available in AppStore..yet.

I have iOS5 and iTunes 10.5.0 (Windows). I've googled/tubed this but can't figure out how to install this .ipa-file.

I've tried:

Drag and drop the file over the left side panel in iTunes. The app is then in the list, but there are no sync button to get the app to my Pad? In youtube I can see that they press a sync button to get the app installed on the Pad, but this seems gone? Have Apple removed this feature? all apps needs to go through Appstore? Only solution to get this app will be to jailbreak it (as I dont want to do that..)?

I've also tried to install the .ipa-file through Dropbox/mail attachment...which doesn't work. iPad cannot open .ipa-files...

Could anyone please help?

Thanks,

Arne