I'm not sure. I was re-installing the rear wheel when the retainer popped out of place. I didn't get to see where it came from. It must install somewhere towards the front of the pads (the opposite side of the push-through pin. The front of the pads will not stay in place; they simply want to drop down.
Here is a link to the caliper fiche at ronayers.com I believe it is marked as part #6 in the diagram. Looks to retain the pads on the opposite side of the pin. Locates against the carrier frame. Let me know if this helps.
This should help http://fiche.ronayers.com/Index.cfm/..._BRAKE_CALIPER
The clip you mention (index 6) attaches to the caliper bracket (index 5) in the orientation shown, straddling the rotor. You will have to remove the caliper and pads from the bracket to fit it properly.
As soon as I posted this I saw wisco919 had already posted it as well. Great minds think alike (or something like that).
If it has already been done, it is safe to assume it is possible to do it.
On the other hand, if it has not been done never assume it is impossible to do it.
------- Rob --------