Alt key from Mac to Windows

[lancers]

I have a mac book pro with a windows keyboard attached. I am connecting to a Windows 7 computer. The problem I am having is that it doesn't send the correlating Windows keys correctly (at least not all of them). For example, shift+tab to move up one field in a web form. The most common problem is with the alt key. Alt+Tab works, but not Alt+Shift+Tab, not almost any combination of Alt within applications such as Microsoft Office (i.e. Alt+S in Outlook). I am a keyboard guy so this is real frustrating to have to be constantly moving back to my mouse to click something. How can I get Teamviewer to pass alt keys, etc.? Any help appreciated. Thanks!