Newbie Question Regarding Sonar X3 (Studio) and Laptop Audio

All,
Total newbie here to Sonar. Want to do mostly mixing of recordings that are already done. At least for now. Anyway, I have purchased Studio, and am about to upgrade computers to run it on. I want to go with a laptop, for portability. I have a very nice, existing audio system, with the receiver/amp having HDMI inputs. My question is, can I get 5.1 or 7.1 Sonar mixes to go to my amp via the HDMI (I assume laptop or desktop would not matter for the HDMI source), or will I need a PC with a dedicated 5.1 surround card with discreet outputs into analog surround inputs on the receiver? 
I really want to mix in surround, and my audio room will be a great place to do it. I just don't want to purchase a PC that is not capable of outputting it.
Any and all help is appreciated.

Jim,
Thanks for the information. I will probably go with the tower option. I am sure that I will start out doing nothing but stereo, but want to eventually mix surround.
It is just for fun at this point, and I am just starting out in the "mixing" interest, but I do have a pretty good environment to do it in. I have about $20K of 7.1 audio system in a studio / room that I have designed and acousticized (if that is even a word) myself (acoustic panels, bass traps, non-multiple dimensions, etc). And, I have a great source of original track material, as I have a professional jazz guitarist neighbor who has given me permission to work with his master tracks at any time.
Thanks for your input. My first fear was whether or not I could get proper 5.1 or 7.1 playback out of the HDMI of a laptop with its capabilities. I was concerned that it would require a dedicated, very high end audio card to handle proper reproduction. You have helped solidify that decision.
 
Thanks again, 
 
Todd Orme
torme@yesco.com

Actually I see no outputs in Sonar for my HDMI or High Definition Nvidia HD Audio.  HDMI is only an output device.
Of course I am using Sonar 7 so X1 or X2 I do not know about or if that has been changed. But I would say is if the audio/interface (you will need drivers from the manufacturer to do surround sound - Creative Labs had such drivers - but the soundcard was crap compared to an professional audio interface which with mine is only stereo) has no drivers for or included with the audio interface and those would have to have listed the HDMI device for Windows with those. Since Windows has its own driversfor that also but I use Nividia drivers for it since I have a Nvidia graphics card (perhaps my computer's HDMI is not actually hooked up and I would have to check the BIOS for that since it is a cheap computer), the only way HDMI is enabled for Windows with my setup is because of the graphics card. (the HD audio device is listed in Windows as an ouput but not in Sonar because I suppose of the audio interface drivers.)
 
That is all I can say about that and I would have to do a lot of checking first to see if that is even possible (to use HDMI) for anything audio, since HDMI is thought of more like a video and audio sending device that I think (look it up in Wikipedia) can handle 8 channels of sound but then there may be other factors like Dolby Surround and all of that which movies have on DVD's and equipment (probably way more expensive) to do it with in the first place.
 
Of course the Nvidia Control Panel states that I have no Display capable of handling it so it is greyed out.
A computer monitor would have to have speakers in the monitor or an audio connection out of it to use HDMI to it in the first place and I know people play computer games and use HDMI to go to their HD TV to use like a computer monitor which also has speakers in it for the computer games (something like playing a *.mp3 file - speakers depending how good for audio sounds anyway).