--enable-trans-sid and passing other variables in the url

I have enabled trans-sid to automagically put the PHPSESSID=09834092384902834092 on my links. But I can't figure out how to do this so that I can pass other variables in the url as well. If I do it like this: <a href="signup.php?test=testvar">Sign Up</a> I get this as the url: http://server-name/signup.php??PHPSESSID=50e0a2ef9276809201c1d9eeba041ffftest=testvar That's not right. ^^ ^^^^^^^^ If I do it like this: <a href="signup.php&test=testvar">Sign Up</a> I get this: http://server-name/signup.php&?PHPSESSID=2333c673957e538fca6c3eee43813887test=testvar That's not right either ^^ ^^^^^^^^^ The documentation is limited to say the least on this functionality. It is mentioned once on the php web site, but never fully explained. Thanks, Keith