Using non-HDMI receiver with HDMI Projector and Blu-Ray

[Sir Terrence the Terrible]

Does your receiver have analog audio 5.1 in?
Does your BR player have analog audio 5.1 out?
If so, you could still get the HD audio formats. If not, then the optical or coaxial digital audio from Blu-ray to receiver will sound great as Mr. P pointed out.

The HDMI to projector works perfectly.

The only problem with going separate routes for audio and video, is syncing issues which are a huge problem. HDMI uses a word clock to line sync the video and audio. If you have the video passing through the clock without the audio, they will get out of sync very quickly, and there is no way to accurately correct it. If you use the analog in's, you should use the component ins at the projector as well.