Ok here goes...
Don't be too nervous. Have a little confidence in your training. Go there and whatever happens learn from your experiences. It's not every day you get the opportunity to match up against someone from another MA. (unless you study MMA that is)
As to technique here's my 2p's worth:
Always keep your guard up by your face (fists somewhere in the chin to eye region). Keep your elbows in by your sides to protect your floating ribs. NEVER LET YOUR GUARD DOWN. Believe me it hurts like hell, especially against kicks.
Keep moving around. Circle your opponent. This will force them to move to face you, possibly opening up some of their guard.
Imho since you are a Karateka, play a close in game if you can. Try fast jabs to the face and try to combo a second and third punch to the face if you hit. I don't think it's a good idea to try and kick at all, they'll have a huge advantage there. If you do kick aim for the floating rib, it's the lowest target possible according to the no kicks below the waist rule. Only kick if you see his guard down.
No fancy stuff! Unless you want to end up KOed.
Are knees allowed, how about elbows? If they are then you can execute them very effectively at trapping range to take advantage of weaknesses in the opponents guard.
Good luck with your match! I hope you have an easy win.
[This message has been edited by Leo_E_49 (edited 02-28-2005).]