Burn Data CD with Long Playlist Fails

My car stereo claims to be able to play data CD's in MP3 or WMA format of
arbitrary length.

When I try to burn a long playlist in WMP 11 as a 700MB DATA CD it seems to
stop at about 80 minutes of content even though the CD is formatted as data
not audio and when I open it in Explorer it shows as ~10% used. Since
Explorer can see the files and directory structure there is no doubt that it
is recording in data not audio mode.

I understand the 80 minute limitation in an audio CD at 80 min but am at a
loss for what's going on with the limitation in data CD-R mode. Can someone
explain how to get WMP11 to create an arbitrary time CD using the full data
capacity? Or is this a bug?

Thanks

NikTesla