Raw phonemes is something that I think only Sphinx 3 does, and IIRC with several caveats. I believe that the task you are doing is known to be very difficult to get good results for. There is an acoustic model called tidgits in [OPENEARS]/CMULibraries/pocketsphinx-0.6.1/model/hmm/en/tidigits with an accompanying language model in [OPENEARS]/CMULibraries/pocketsphinx-0.6.1/model/lm/en that I think is specifically oriented towards recognizing numbers that you might want to try instead of hub4wsj_sc_8k and your custom LM, although I’ve never used it myself so I can’t make any promises.