How to get the ENCTYPE of a form

I have an ASP page that needs to handle two different types of forms -- the first being the default enctype: "form/url-encoded", and the second (for file uploading) being of enctype "multipart/form-data".  The problem is this:

The ASP Request object will not work if the encoding is multipart.  I can't use the Request object to tell if the encoding is (or isn't) multipart, because if it is, once I use the Request object, I can no longer do a binary read.  Also, if I attempt a binary read and the encoding is form/url-encoded, then I get a "corrupt MIME headers" error.

So the question is -- how can I tell the ENCTYPE encoding of a form without using the request object AND without using "on error resume next"

Thanks