federal secretary desk

I am looking for the hardware used to auto extend and retract the writing shelf supports. Also the hinges. I purchased the plans from Rocklers and they have hinges ( not what is shown in the plan set) but do not list anything for the shelf support system. Since I already cut the material to the plan I am stuck with either pitching out very expensive veneered plywood or locating the hardware .Anyone out there build this item per the plan?
Just for the record the plans are somewhat sketchy in that they refer to detail on page 96 which does not exist in the plan set.
Being a beginner in woodworking the plans to me were missing a lot of other detail.

jimmac

-- James Mack