Here's a minor tweak...

Your source mentions that you want to pause the player but can't, because sending a play/pause will UNPAUSE the player if it's already paused... But what about standby?

Replace line 300 with:
ftp.sendcmd('SITE button source.L')

and the Empeg will be placed in sleepy-mode.. On my Empeg, it doesn't seem to wake it if it's already in standby, but it will reliably put it there.