OK, so I've taken another look at the sound warning capability of some other Carin-compatible units. An interesting thought is that all the tags that need to be added to enable this feature exist in the current v30 firmware. i.e. the BMW system must already have some degree of capability to read these tags, probably because of shared code and maps with the other systems, even if it ignores them. e.g.

TPD-FEATURE SPEED_ALERTS=100
TPD-ACCESS-ALERT 75

The .url and .idx files also contain slightly different information to the ones we're using for normal POI, but this is not a hurdle.

What's not obvious with the BMW system though, is where to put the sound file, as there's no comparable location to the flash memory based navigation systems that have the sound feature. So this is where we start getting into trouble, as I doubt that the OS9000 operating system can play .WAV files. However as iDrive uses Windows CE, there is perhaps still hope that something might work here.

For more information, see the French site:
http://www.google.com.au/search?q=SA...B2GGGL_enGB175
or translated by Google into English:
http://translate.google.com/translate?hl=en&sl=fr&u=http://www.gpspassion.com/forumsen/topic.asp%3FTOPIC_ID%3D59532%26whichpage%3D8&sa=X& oi=translate&resnum=4&ct=result&prev=/search%3Fq%3DSAUVEGARDEGPSV2MODIFIE.rar%26hl%3Den% 26rlz%3D1B2GGGL_enGB175

(The interesting bit is the .rar file)

PS: My MKIV Nav crashes if I insert a map with audio warnings enabled. Anyone seen anything different...?