I would not recommend trying to do this.

1.) It doesn't anonymize you any more than you already are (bitcoin is already anonymous and decentralized)

2.) Bitcoin client is essentially a torrent client. You are not supposed to run this on tor--it harms anonymity and puts undue stress on the network.

3.) Using tor browsing is safe enough--your goings on will not be tracked.  If you're worried about it, use something like instawallet.