You can manually edit the field.
I just tested the same thing and it worked as expected at the URL of the static resource. I think maybe you are battling some other demons here, but I'm not sure what. Perhaps this is a babel issue?
Is there some fundamental reason why static resources should not be able to use a Media Source? Or is it just a matter of getting the code modified to have them do so? And if it is possible, and reasonable, how would I go about getting such a thing on a fast track? I had thought "Emergency Support", but this isn't exactly an emergency, just something I'd like to get done in the near future, as I have an immediate use case for it.
I have in mind being able to implement a single corporate-wide document repository, where .pdf and .doc documents will reside. All documents relating to a given product will be listed in a MIGXdb TV using static resources and a custom Media Source into that corporate repository.
So who do I talk to if I want to pay for this to be done? Or am I being presumptuous?