filter protocol

I was coding a small dialog for my bachelor theses. There is a text box where you can enter an URL address. So, before submitting the form I validate that text box with check_url() function. The problem is, that my address starts with MMS. It's something like that: mms://www.server.lt/directory/file. So, after check_url() function the result is: //www.server.lt/directory/file. I was googling for the solution and I've finally found it. The problem is in file modules/filter/filter.module file, line 1182. "MMS" is not in the list of allowed protocols.