[vdr] ledxmit-irsend to STB before channel-change??

I'm looking for a way to execute a command whenever a channel change is selected. I think part of the 'sky' plugin is close to what I want - without the stream type changing part.

I have a PVR-150 running with the pvrinput plugin, attached via composite to a digital cable STB. I have led-xmit (from the Myth pages) working from the command line, but need a way for VDR to execute a command each time a channel-change is requested, either for a recording or manually:

/usr/local/lirc-ledxmit/bin/ledxmit-irsend SEND_ONCE ADB_ICAN3000 <channel#>

Has anyone done anything like this?