T41P BLF and CallPickup issue

[systemstateit]

Hi,
I've seen some other threads on this I understand how to get this working, however it does not appear to be able to work the way I want it to.

I use a hosted PBX (asterisk underneath), and I want a DSS key to be both a BLF monitoring an extension and to be able to pickup the call to that extension.

For example I am 101 and want to monitor 109.
Value -> 109 Label -> Bob Extensions -> *8 (or just set it globally in advance menu)
If I put in the details as instructed the phone monitors 109 correctly and flashes RED when a call comes in. If I press the line key it tries to call *8109 and I get a 'not a valid destination' error
Problem is the extensions on the hosted PBX are all part of a pickup group, so all I really need to do is dial *8 with nothing afterwards and it picks the call up.
Setting the DSS key as a direct pickup/group pickup works as it will just dial *8, but then I don't get the lamp indicator.

Is there a way to monitor an extension without it trying to tack that extension number on after *8?

Currently I have just used a spare DSS key as a direct pickup line while still using BLF to monitor/speed dial, but it's a bit of a hack.

Note: This is working on our cisco spa303 phones using extended function: fnc=blf+sd+cp;sub=109@pbx.hosted.provider

Thanks