IBM Infoprint 4100 help

[KirkMVPGroup]

Does anyone have any experience with preprinted, tractorless forms and the specifications for the "registration" marks? We recently printed an 8.25" x 11" form two up with a 1/16" gutter on our Didde. The repeat on our Didde is 17". We can't get the form to print through our Infoprint 4100 because the pre-printed "registration" mark isn't equal distances apart due to the necessary gutter on our print piece. According to the operator of the Infoprint, the registration mark needs to be an equal distance from the next mark. Is there a manual way to trick the machine to read only one of the marks? Any other ideas are welcome. Thank you for your time.