Peter,
I have had to face a similar problem in an African country where helicopters were allowed to operate VFR only.
This, beeing not compatible with an offshore scope of operation, we had to offer local CAA officials a trip to Aberdeen to make them believe helicopters could safely fly in clouds at night and, when adapting speed, in reduced visibility.
Back home, they worked out an "helicopter SID and STAR" , separated from "planked-wing" procedures, and allowing us to offshore depart and arrive at transition altitude in their controlled area.
The next stage would have been to make official a lower altitude than transition altitude (2600') over off-shore sectors and eventually drifting to "reduced visibility helicopter lanes" to get completly rid of IFR procedures (not very confortable in stormy conditions with "adapted" fuel reserves and a "virtual" divertion)
But this scheme sadly never evolved, because controllers becoming aware of off-shore helicopters equipment and crew experience, cleared for a "visual approach" most of the time when requested by a crew.
Reporting points on theses SID an STARS where determined on VOR/DME use.
But, as a matter of fact, helicopters are at ease in the shadow area between this cristal clear part of regulations and the darkness of unlawfull chaos (sometimes they even feel better in chaos !
)