For smaller "valuables" you should consider a Console Vault, easy to install, very secure and things can be placed in it very discretely vs. standing outside the AV and using the saddlebags which aren't as secure or water tight.
http://www.consolevault.com/
They do custom work I believe and you may want to contact them about a secure box under the rear seat for larger things.
FYI it helps if you put your year and model AV in your signature because some answers to questions vary from year to year or model type. That way you won't have to repeat yourself when asking other questions.