idle stumbles while a/c is turned on (E30 M42)

[BillyInJimny]

Hi guys,
Im new to E30 and i just need a bit of help.
Since the E36 A/C system is different from E30, there's a idle stumbling problem after I turn on A/C (i.e. there's no signal sent from DME to ICV, because the wiring not match).
Some E30 owners in Taiwan who use a relay to connect from A/C switch to ICV (i.e. ICV always running after A/C switch on), but I don't think that's a good idea.

Could anybody give me some tips and or advice on the A/C system wiring (i.e. How to deal with the A/C signal)?

Here're some detail information of my E30:
Chassis: 1989 BMW E30 318i
Engine: M42DISA
DME #: 0 261 200 990

Thanks! 

[BillyInJimny]

Here's wiring table.
Any advice would be greatly appreciated.