Assassin's Creed Regulation Weapons

I am creating 2 Assassin's Creed Revelations costumes for a friend and I to wear to Supanova Perth, however we have hit a dilemma. The costume is bang on track so far, but what's an Assassin without his (or her in my case) weapons?
A snag has appeared in the shape of Supanova weapons regulations. I'm not familiar with international conventions and how their weapon policies work, but as far as Supanova are concerned "anything with a point, lots of weight behind it and sharp is not deemed appropriate for this event and will be confiscated at the door".
The convention is in a week! I desperately need to figure out what I can use to make realistic looking weapons for us to take that don't break the policies Supanova have laid down to protect everyone's eye-balls and prevent lawsuits. Even A harmless dagger would be fine, I'm just not sure where to start. If it turns out that we'll just have to turn up with empty belts then so-be-it.

Can anyone help me out?

Foam, of course!

I've never used foam. I don't even know where to start. Pointers? Possible helpful links?

theres tonnes of foam building stuff in the costume section look at the xrobots stuff among others which could easily used for your weapons http://www.therpf.com/f24/how-plasti...pieces-146539/