Do you know which box is delivering the service? There are a couple of different ways that this could be delivered and lots of incompatabilities between muxes. Cisco 15454 can do this as can Nortel OM and Lucent Metro. The 454 is horrifically expensive though but if you are already a cisco shop it could be the simplest option. Downside to all these devices are the management systems are somewhat not what you'll be used too. might be worth asking the carrier to do this for you as for them its could simply be a card in the existing mux (assuming it is a SDH service).
Neil