I have to say that I too am curious as to why you would want to covert to .wmv. If it is for generic playability on windows, then maybe you could covert from .mov to .avi, thus it is easily playable on Linux, Mac, and Windows.
I'm a web developer, so I understand that sometimes there is a need to convert to .wmv (i.e. that's what the client wants). So first off, what are you using to convert your .mov files? Flip4mac? Other?
The reason for converting my .mov to a .wmp or .wmv is so my wife's work laptop can view the flick. The computer is software protected and I cannot download Quicktime to her computer. Damn corporate world!
I have tried using the .avi, but the quality is terrible.
Neither final cut or imovie (both based on quicktime) can convert to .wmv with the standard codecs installed on a mac. You need a third party application like flip4mac, mp4converter, etc... to give quicktime the proper codec for the conversion.
That being said, your initial question was that you could convert to .wmv but the clips were truncated at 22 seconds. Obviously, whatever codec you have intstalled doesn't work and we don't know the manufacturer.
My recommendation is to use flip4mac (http://www.flip4mac.com), they have a few versions, get the WMV Studio version. This will allow you to create the files you need.