Starting a fixed length loop in Loop31

[Mark Sottilaro <sine@zerocrossing.net>]

OK, a while ago Kim mentioned that one could set up the EDP to start
recording, go a certian preset amount of bars, and then auto end the loop,
going into overdub.  I'm synched to the midi clock of a drum machine (a 
Roland
MC-307) and have it set up so it quantizes my loop (waits for the "one" to
start recording)

I asked this a little while ago, and the response was, "really ought to get
Loop4..." but I'm sure I heard of this function long before Loop4 was out.
I've been over the manual, and it doesn't seem obvious to me.

anyone?

Mark Sottilaro