VIOP and inbound SMS

I have a SMS capable DECT phone which sits behind a traditional PBX which I would like to be able to recieve SMS messages on.

It doesn't look like I am going to be able to get the message through the PBX so am looking into the possibility of using a voip service for this.

Does any one know

a) if this is possible
b) which providers support/allow this

Also can anyone recommend an ATA which will allow this to work, and allow me to continue to use the phone as a normal extension on our PBX,

mant thanks