[LAD] rtaudio jack/alsa problem..

I have a problem with a a project I am helping out with (aldrin), which uses rtaudio version 3.0.3 for jack/alsa/oss handling. When aldrin starts, it calls libzzub to detect all possible sound input/output, and then selects the best one (defaulting to jack if it is running). This is working fine on my system if I have selected a sub-device from my SBLive card as the sound input/output device (hw:0,3 works fine). However, if I select the default jack output (hw:0), I get loads of xruns when aldrin starts, then jack dies. Doing some further testing, if I disable detection of alsa after libzzub successfully finds a jack device, then hw:0 will work fine without any xruns, so it seems that there is some conflict between jack and alsa. Lastly, I noted that if I select hw:0,3 as the output for jack, then libzzub/rtaudio does not pick up hw:0,3 as a valid alsa output (presumably correctly assigning it as a jack output), whereas if I am using hw:0 as the output for jack, then hw:0,0 is also detected as a valid ALSA device.. this makes me think the xruns are caused by some conflict. The lead dev for libzzub is not happy with my patch to libzzub not to detect alsa if jack is found, and would prefer a fix to the rtaudio code. I am not really sure where to start with this, since I am not 100% sure what is going on. I would really appreciate it if anyone could help with this.. Best wishes, James