EDI ASN Summary

We have create a bunch of new EDI setups. We have a bunch of sales orders shipping. From time to time we have a BOL that does not populate the EDI ASN Summary lines and thus the EDI ASN (856) file does not create. Is there an interanal trigger somewhere that causes this and can we un-post the BOL, set the required flag and attempt again?

We are running NAV 2009 R2 in RTC with Lanham ESHIP.