Cold Roof Attachment to SIP's

I have a timberframe under construction with a 14/12 roof pitch, and 8" Structural Insulated Panels. I am planning on installing a cold roof over the panels with 2 X 2's on 16" centers and covered with 1/2" OSB. My roofer has questioned the attachment of the 2 X 2's to OSB on a steep pitch, with nothing "substantial" to anchor to. Are there any thoughts on the proper method of attachment in this application?

David,

My immediate reaction would be to use construction adhesive and deck screws to attach the sleepers. Some of this answer depends on the type of roof to be installed and thickness of both the OSB on the panels and the nail base for the roofing.