I'm not sure if this is an option for you, but I use Sipura 3000 (FXO, FXS) and I don't have any problems with zaptel mess up in LMCE or Pluto.
I had a look at that sipura 3000. Looks like that takes the pstn pots and hand off ethernet back to the internal network. Is that correct?
If so, I don't think that requires the zaptel driver and uses SIP instead. PLEASE.. correct me if i"m wrong..
I havent had a chance to play with the telephony features in LMCE, but I plan on testing zap channels using the AMP config pages. I did have zaptel working with Pluto before switching to LMCE, but that required building zaptel myself. Anyway, I need to poke at this a bit more and see what I can find out.
BTW.. How well does that sipura 3000 work with connecting your pstn service. Do you have any issues with it?