There's been multiple threads on this, I've been working with the Microsoft folks to chase this one down. This is the feeback i got from them.

If a schema contains both “xsd:date” with nillable=true and “xsd:dateTime” with nillable=true, we will import either both as “date” or both as “dateTime”. In your case, both probably get imported as “date”, hence the time component cases a failure. This is a known bug and there is a hotfix available (KB 925272), available by calling PSS.

I tried out the hotfix on the failing test case i had and it addressed the issue, so if you're seeing this problem, you can either call Microsoft PSS and get the hotfix, or if you don't need access to any of the xsd:date fields, you can modify the wsdl by hand to remove these elements, and re-import it, and everything should be good.