Hello,
I have a track I recorded which is just midi sounds, using a soundfont library. (Soundblaster Live, Windows XP).
If tracks are recorded this way, they play back fine in the mix, but will not render to .wav, nor will track effects work. Is it not possible or am I missing a step? Thanks.
If you are using MIDI the sound-source is external (the sound is not produced within Renoise) and can therefore not possibly be rendered by Renoise.
As long as the sound is produced inside the computer and you have a full duplex card it is ofcourse possible to do it in one way or another… But think about it if you are using an external hardware-synth for example 
True, true.
For those who use soundfonts:
I downloaded Vienna Soundfont Studio (free from Creative Lab’s site). You can export all the samples from a soundfont, and from there, bring them into Renoise and map the instrument. It doesn’t take too long, and your soundfonts don’t go to waste.
or you use a SF2-playback VSTi … then you can render it with renoise.