Datsun,
I am not sure what Foma is using but I speculate it may be close to what Ilford is suggesting. If contrast is your only worry, your current bleach may be ok.
Lack of contrast could also mean low solvent effect. AFAIK Foma kit does not have a halide solvent as it uses same developer solution for fist and second bath.
You could add a silver halide solvent bath after first developer (~5g/l hypo @ 10 min as starting point) and adjust time accordingly if the contrast is not as per your liking. If you do this a water wash/ stop is necessary after first developer to stop developer action.
Also Agitation in bleaching is very important. Vigorously agitate the tank during entire time while bleaching.
P.S. If you have not already done so, please read Jens Osbahr's pdf. It is quite informative.