Can I claim treaty while filing joint 1040?

My hu*****and is a RA in 2005 and I am NRA, both of us are F-1 from 1/1/05 to 9/30/05, and H1-b since 10/1/05. We all get the 1042-s with $5000 on it. We can select to file joint 1040 in 2005, can we claim the $5000 as treaty benefit?

I saw someone wrote in a post: you can't claim treat benefit if filing joint 1040. Is this correct? I didn't see any such regulation in publication 519. Where is the regulation is?