This may or may not be helpful, but since the orders already exist, have you tried just calling the OrderJobWizard BO?
warnings = "";
errors = "";
exceptions = "";
CallService<OrderJobWizSvcContract>( jobWiz => {
try {
//__ Set OrderJobWizard Dataset
var ds = jobWiz.SelectAll(orderNum, true, true, true, true);
/* Params:
int OrderNum,
bool CreateJob,
bool GetDetails,
bool ScheduleJob,
bool ReleaseJob;
*/
jobWiz.ValidateJobs( ref ds, out warnings );
jobWiz.CreateJobs( ref ds, out errors );
}
catch ( System.Exception ex ) {
exceptions = $"{ex}";
}
});