Yes, you can!*
*As long as you leave all the copyright information intact, don't edit the comic at all.
Also, link back to either Kaerwyn's main page at http://kaerwyn.blacktapestries.com/ or the specific comic URL of your comic on it's main site. For example, if your character was on Issue 10 Page 98, you can link to http://kaerwyn.blacktapestries.com/comic/667
And lastly DO NOT post your cameo comic before it goes public. Remember you get to see them about 1-2 days before it goes public. If people start posting cameos ahead of time, then I'm not going to post them early anymore. So just do me that favor at least.
So there you go. Post away.