Look here on the wizards site,right hand side...The fix it club..scroll down till you see..Jims front end repair..half way down that page you will see how he repaired a crack...Click here
Also a good idea to drill a small hole at the end of the crack to stop it spreading.
This works in all materials, as far as I'm aware.
Probably a good idea to try & find the cause as well. Someone I know found their Lunar had a crack in the front panel as the floor had come away from the body somewhere & the front panel was left supporting too much weight/stress. (can't remember the details, but that was the gist of it).