Hey there. Forgive me if I misunderstood you, for I'd hate to be patronizing. My sound card records only in mono, so I have to manually duplicate channels to make it sound stereo. Here's what I do in Sound Forge XP: When you have finished recording your guitar part, the recording will display as a monaural waveform, usually a waveform in the left channel but not in the right. As I explain, I will mention keyboard shortcuts, like copying using the control key and the C together. Click and drag your mouse over the channel that you wish to duplicate (the top one) and then choose to "Copy" (ctrl+.) This function will put the single channel in SoundForges clipboard. Then "Select All" with ctrl+A... this should highlight both channels. Next, press ctrl+V to paste over the highlighted channels. A dialog box will come up, and simply choose to paste over "both channels."
That should do the trick for you. Also, SoundForge has a nifty feature called Wavehammer, which has a preset for acoustic guitars to enhance their presence. Additionally, Wavehammer also has a preset called "Master for 16-bit," which brightens tone, compresses your file, and can be used as a volume maximizer. Just make sure to add a little light reverb to your file before using wavehammer. Anyway, I sure hope that this is informative and helpful. I'm self taught, so I could be doing everything in the world wrong. Good Luck