electronic brain surgery since 2001

Keep mixed line endings in VIM?

Dear lazyweb, I kindly ask for your help.

I have to work with a bunch of files checked out from a customers subversion repository. Those files have a mix of Unix and DOS style line endings. I know how to correct those line endings to either Unix or DOS in VIM. But I don't want this because it will create bigger patches than it should and it's hard for the customer to spot what I really changed. Unfortunately VIM thinks it should make me aware of the DOS line endings by displaying a ^M.

So the question is: How can I hide this ^M, without changing any existing line endings?

I tried :set ff=dos and :set ff=unix, but because of the mixed endings in the file they do nothing.

Any ideas?