Will my older aux siren work with Simplisafe2 system?

I purchased my system in mid August of last year (2011) and was considering getting the upgraded Simplisafe2 system during this limited offer only with intention of possibly utiliizing some of the newer features at a future date. I read somewhere that the older aux sirens will not work with this system? Can you validate this information?

Since my system layout has the base station quietly and safely hidden away in an attic, I rely on the aux siren to (destroy eardrums) be the auditory part of my security sytem. It is a somewhat expensive device to replace at $60 and would probably discourage me from purchasing the upgraded system since everything works perfectly now....and the additional features are not as necessary as the core "burgulary" component of the system [for me]...

Thank you and let me know!