I didn't even know there was a portable version of FF3, but I'm glad you mentioned it. It does make sense that the signature wouldn't necessairly save as they are saved in your Firefox user profile. Basically, there is a JavaScript call that I make within the add-on to tell Firefox to store the sig. as a preference. Unfortunately, I don't really have teh time and resources to figure this one out, and it's even possible that that portable version of FF will be improved soon anyway, so I'm going to have to leave this bug as is for the moment. If anyone has time to look at the code and figure out a workaround, I would be very greatful!