I'm afraid the only ons that support SDH trunk card and Fiber-Channel client interface is the ONS 15454E. I checked and there is no lower class device that has Fiber Channel interfaces (15530 is DWDM device, no SDH trunk cards).
I'll suggest to verify the service you're asking for to the telco. Usually the carrier provides also an ADM that may have different kind of interfaces (ethernet or also FC). Connecting directly to an existing SDH network may require some more consideration, particularly if existing SDH devices are non Cisco (protection scheme, DCC transport). You may always use MDS 9216i to connect 2 SAN using IPFC over Gigabit (as ADM you may use a 1531 or 15327).
Stefano
