My engineer and sips supplier both recomended hanging the ledger board inside the osb. It makes for a stronger structure. We used panel screws closely spaced screwed from the outside to the board.

For anyone interested, the bond strength between a SIP's skin material and its EPS core is around 20psi (ultimate). Lets say one glues and screws a 16" wide piece of 12" rim joist to the face of a wood SIP. Then one hangs a 12" joist of any length to the middle of that rim joist. The area of the mentioned floor assembly engaging the skin of the SIP is 16" x 12" = 192 sq. in. If you now multiply this by the 20lbs. per sq. in. bond strength you would get 3840lbs. This is the amount of force it would take to pull the floor assembly mentioned and portion of SIP skin away from the SIP wall at each joist (spacing 16" O.C.). Adding screws from the outside through the SIP and into the floor system is unnecessary unless the design needs the floor system to provide some lateral stability to the building.