Found some information on the TU204C from the Tupolev Website.
https://web.archive.org/web/20100503081923/http://www.tupolev.ru:80/english/Show.asp?SectionID=35The key bit of info is this:
"TU-204C is a mid-range cargo aircraft is based on TU-204-100 passenger aircraft. TU-204-C is designed to carry cargo of 30 000 kg in international class containers for the ranges up to 2400 km or cargo of 13800 kg for the range of 6800 km. TU-204C a/c is provided with cargo door at LH side; passenger cabin is replaced by main cargo deck provided with loading/unloading ANCRA System (USA). Cargo compartment area is equal to 164,4 m2. Under the main cargo deck there are two baggage-cargo holds. The forward cargo hold area is equal to 14,7 m2, the aft one – 28,3 m2. TU-204C aircraft are used to carry cargo both within Russian Federation and abroad."
Additional information can be found on old captures of the UAC website:
https://web.archive.org/web/20130429092432/http://www.uacrussia.ru:80/en/models/civil/tu_204_214/tu-204c/Key info from the above source is:
"The performance characteristics of the Tu-204C are the same as of the Tu-204-100. The crew’s cockpit copies the Tu-204-100’s cockpit.
Cargo compartment volume is 164.4 m3. Volume of the front baggage-cargo compartment is 14.7m3. The volume of the rear baggage-cargo compartment is 28.3 m3.
Cargo door dimensions: 3,408 x 2,080 mm; front baggage-cargo compartment door: 1,350x1,162 mm; rear baggage-cargo department door – 1,350 x 1,162 mm.
A single cargo unit weight can reach 3,100 kg. The maximum longitudinal size of a long item of cargo is 10 meters. Long size items of cargo are transported on standard pallets while being locked on to the pallets. A single long item of cargo could be placed on two, three or four pallets.
The cargo compartment can store six “narrow” type 2 pallets (88" х 108" or 2,235 x 2,747 mm) or ten type 3pallets (53" х 88" or 1,346 х 2,235 mm) for container transportation.
The Tu-204C is equipped with a cargo handling system manufactured by ANCRA (USA)."
Hope the above information is useful