Er...hm. Well, one thing to fix first: it's "type=date", not "type=day". But I don't think that should be causing your problem? Especially with it returning back a signature invalid message. My only other thoughts would be:
* The library or your code is incorrectly assuming that the extra parameters are GET parameters, when they're actually part of the URL itself. What does the call look like through the python library you're using? * There's some URL encoding issue going on where the semicolons or = signs are not being URL encoded before going into the signature.
Let me know a bit more about how you're generating the signature, and I can try to think a little bit more (but also go ahead and fix up the "type=date" just to make sure that's not causing any other issues).