Automatic linefeed-conversion

Hello!

We have a SVN-repository to which both windows- and linux-users connect.
Because there are different linefeeds for textfiles, it would be nice if
SVN could convert all checkins to unix-style using a program like flip.

My first guess was a hook-script, but the SVN-book says in a warning

| Do not attempt to modify the transaction using hook scripts.

So my question: Is there a way to convert textfiles automatically at the
checkin?

TIA
 Stephan