Okay, lets try & work through this one for you.
1/. What is the samplerate of the project? You say you exported to both 24/96 and 16/44.1 - it is better to stick to the same sample rate throughout.
2/. The 6 mono WAV files - again, what samplerate & bit depth are they?
To get your signal working correctly in your system, you need to have either a Dolby Digital (AC3) stream, or a DTS stream coming from the SP-DIF or CoAxial output of your soundcard into the AV recievers digital inputs.
This is where it can now get complicated, so please bear with me.
A/. Dolby Digital files use a 48KHz samplerate. 44.1KHz will either output unpleasant noise or nothing. Same with DTS files - unless you create DTS-CD files instead.
Both these need to be done with external converters. Apparently BeSweet has
AC3 converters, but they are a bit unreliable & moody - they work for some people & not others.
Your easiest option is going to be
AC3, as it is simpler to find the converters - but I do not use these ones, being lucky enough to own Nuendo, so cannot say where to find them.
Another possible ioption - does your amp have 6 analogue inputs for Surround?
If it does, you can always try outputting the 6 mono WAV files you have from your soundcard straight into your amp, and switching the amp to analogue input. This may help.
Sorry I cannot help more, but getting surround is neither cheap or easy I'm afraid.
You are going to have to spend some money.
Your most reliable option, without going the DVD route, would be to buy the SurCode DTS-CD encoder. It is around $500 or so, and it will take 16 to 24 bit files at 44.1KHz, and multiplex them into a WAV file that can be burned to a CD. www.surcode.com
This would then be played in your normal CD/DVD player into your amp, which has the DTS decoders.
This method is a very good way of getting into true surround at a reasonable quality. It is definitely better than Dolby Digital, as it is a 4:1 compression as opposed to Dolby's 12:1 ratio.
Hope this helps.