[Icecast] Unique Listeners from stats.xsl?

[Frank Steinborn]

Hello,

i need to retrieve the following from a stats.xsl (is it even
possible?):

- Unique Listeners. So if there are 5 listeners on the stream, and two
  of them share an IP it should give "4".
- Stream up or not: If the mountpoint is alive it should print "1",
  otherwise "0".

I'd appreciate any hints, this is a bit urgent. Thanks!

Frank