You can connect two Foxsat HDR's on the same network using custom firmware plus the NASMount package. Each HDR sees the other as an attached USB drive and plays the recordings natively, so there are no problems with selection of correct audio stream. Only downside is that when crossmounted like this the HMT sidecar files can end up with the wrong filepath for their associated TS file, and this then needs to be corrected with the fixfilepaths utility before it will playback correctly on the box it was recorded on.
Using twonkymedia on the Foxsat HDR, I can stream recordings from there to my HDR Fox T2 but, as you are already aware, for HD recordings the audio description track will be chosen as the default and cannot be changed.
This is not a fault on Humax's part. I've determined that the order of the audio streams listed in the program map table (PMT) , is the deciding factor when playing back recordings on third party players. They just use the first audio stream in the list as default. These PMT packets are part of the broadcast stream which, apart from encryption, are just saved '"as-is" when received from the mux.
With HD recordings on the Foxsat, the AC3 track is listed after the audio description track in the PMT table. You can observe this on the HDR itself if you press the audio button. With SD transmissions, the audio description track is listed below the main track, but with HD it's listed above it. The HDR itself is able to select the correct one as the main track, but 3rd party players are not so smart, hence the problem.
I currently have a utility in alpha which can re-order the PMT stream list of HD recordings so that the AC3 stream precedes the audio description stream. This does not require a remux and new nts files do not need to be recreated. The main problem is that the Foxsat does not have the horsepower to do this task quickly. This utility also includes code produced earlier by adrianf36 which corrects the program association table (PAT) packets to contain only one program (works for HD and SD). This makes the TS file format nearer to standard, and as such more compatible with other devices such as DLNA enabled TV's. Resulting file still plays natively on the Foxsat, but now I can stream it to the T2 with correct AC3 audio and also successfully stream it to my Samsung smart TV.