Yes that's what we're trying: blue Superkey > Call Forwarding > Always > destination no.
I did think it was ACD 'interfering' because as I say it does work from internal extensions. I assume setting it administratively suffers the same? We can't do that anyway as we have a restricted access via the hosting providers portal.
Is there absolutely no way around this? We have a requirement for 100% phone coverage so the idea is that if somebody walks away from their desk for whatever reason, they'd put Call Forwarding on (we setup a softkey for this) so they can answer it on the mobile. At the moment if that happens somebody else has to pickup their phone if they're next in line and a call comes in. Then if and only if everyone is logged out, ACD diverts to a pre-set mobile which has to be changed manually depending on who's covering.
We don't expose DIDs to the outside people.
Yes I know it's archaic and I know MiCollab would be the answer but not an easy option due to price. I'm aiming for that in the future, and the free option above is kind of proof of concept.