Loop pedal with spillover/bleed?

[Kröx]

Hi !

I'm trying to build a loop as designed by slacker: http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=52584&g2_serialNumber=1
I'd like to do a version with two switches. One latching to have the loop active, the other one momentary to have the loop only active when pressing.

In the design above, there is only one 2PDT switch shown. Can anybody help me, where or how to add the momentary switch ?