[PROBLEM] Can't play .m4a audio via Shairplay

[Chris83]

I have a number of audio Podcasts in .m4a format (ALAC?) which I can't play via Shairplay.

I'm using the latest build. Normal videos, pictures and mp3 audio are working fine with Shairplay. If I open the RSS feed to the m4a Podcast manually and play it via PAPlayer it also works, but not with the standard OMXPlayer. I already tried to edit the advancedsettings.xml and playercorefactory.xml but to no avail (RSS feed to the m4a file however is using the PAPlayer by default now).

I also picked up that the background in XBMC changes to black if I try to play m4a via shairplay as if it tries to start a video - this doesn't happen with mp3.

Below my changes to advancedsettings.xml:
<audio> <defaultplayer>paplayer</defaultplayer> </audio>

playercorefactory.xml:
<playercorefactory>
<rules name="m4a">
<rule filetypes="m4a" player="PAPlayer" />
<rule mimetypes="audio/x-m4a|audio/mp4a-latm|audio/m4a" player="PAPlayer" />
<rule mimetypes="audio/pcm" player="PAPlayer" />
</rules>
</playercorefactory>


any suggestions what else I could try?