Solomona switched to Cas from London at the end of 2014, after an impressive opening campaign in England.
He switched to the UK after the 2013 campaign, due to a lack of first team opportunities at Melbourne Storm.
Solomona's career took off at London, and his eight tries in 20 games helped secure him a transfer to West Yorkshire.
Denny can play in the centres, on the wing or at full-back, and is a raw but talented player with a big future in the game.
Denny is sponsored by Sys Servers Scada.
*Photograph courtesy of SWPix.