You might try Lenny Sarbin at Shindin Machine for a suitable retract at a bit lower cost. Lenny does good work at a good price and has a great reputation for backing up his product with good customer service.
You might find not being able to obtain the stock retracts for this airplane to be a blessing in disquise. The factory units have a pretty awful reputation. Retracts are one area where I try not to skimp as the low cost units generally end up being much more expensive in the long run.