It's the same set up as shown in your parts book for direct electric start except you need to change the drive to the LH helix drive gear (not RH). The factory offset adapter plate is required.
Can get both the drive and adaptor from:
http://stores.ebay.com/Triodiode-DC-Electric-And-Tractor_W0QQ_trksidZp1638Q2em118Q2el1247
See if you can catch "ol grump" on the BB....he just did a conversion on a D333 recently. (same drill)