If your company Air Operator's Certificate requires that it be two crew, then yes, you may count it as such. I flew PA31's two crew in BC - being a Designated Mountainous Region, Transport Canada required it. You need to fill in an MCC exemption form from the CAA and I think a fee of forty something quid.
You will also need a type written letter from the Chief Pilot stating this, or a copy of the ops manual / certificate where it states two crew.