Hi,
I believe it all comes down to 3 options:
Option 1: Use the Pitney Bowes Scan code object in PlanetPress Design. This requires that you first contact your Pitney Bowes representative, and may involve costs.
Option 2: An OMR is just a bunch of lines and the scanning device just checks for the presence or absence of marks at specific locations. So you could create your own OMR using Box objects and conditions in PlanetPress Design. This requires that you possess the documentation about what each possible mark could mean, where to place them, etc. This should be available from the device manufacturer. One drawback of this approach is that you have to do everything from scratch, and adding functionnalities such as a Wrap Around Sequence (WAS) can be cumbersome.
Option 3: You can try another standalone software that Objectif Lune created expressedly for inserting Scan Marks on PDFS for use on inserting devices: PlanetPress EnvelopeNOW. More details here:
http://ppenvelopenow.com/Hope this helps!