I believe it does do what you think, but Indigo doesn't fully support it yet. You can, however, experiment around with it. I never have, so caveat emptor on this functionality.
To enable the detached load functionality you'll need to send the KeypadLinc (KPL) a raw command:
1) Choose the
Interfaces->INSTEON->Execute Raw INSTEON Command... menu item.
2) Select your KPL device and enter
0x20 and
0x1B for command bytes 1 and 2.
3) Select the
Send extended message checkbox, and press the
Execute button.
Note I'm not positive extended message should be enable, but I'm pretty sure it will be required since that KPL is i2CS firmware. Also if you want to revert back to disable the detached mode then repeat above but send the bytes
0x20 and
0x1A.
What happens when it is in detached mode? Good question. I think that the first (main) button should no longer directly control the load. Instead to control the load you have to create a link to group #9 which you discovered earlier in the link management dialog. You should be able to have the KPL #1 link to group #9 on KPL #2 to control its load. Likewise, you can create and Indigo PowerLinc group/scene to control group #9 on the KPL (and thus control the load).
Some things that will likely be problems:
1) Indigo cannot create internal self referencing links in a module. So you
cannot create a link for button #1 to group #9 to control the load once it is detached. You can create that link to another KPL, but not to the KPL itself. You can, however, work around this by creating an Indigo Trigger that on receiving KPL button #1 button press sends a PowerLinc Group/Scene back to the same KPL (for group #9). There will be a slight delay, but it might be tolerable.
2) Indigo isn't going to know how to reflect the ON/OFF state of group #9. That is, Indigo will always show the ON/OFF state based on the KPL button #1, even if the load is detached and really on group #9. You could manage the state manually using Triggers and have it reflected in a variable and then use a Virtual Device to accurately show the load on/off state (and you can have the Virtual Device control the load via the PowerLinc Group #9 actions).
Good luck, and let us know if it works. Definitely uncharted waters.