From my understanding, you would use the 'Scan sales data from other systems' option in Softrak Sales Analysis to get Invoice History data into SR.

The steps in SR would be:
3. Maintain Sales Analysis Data
1. Retrieve Sales Data
4. Scan Sales Data from Other Systems
4. Scan Softline's Invoice History

I would imagine this depends on how you have Invoice History setup as well, but cannot say for sure.

Regards

Sorry, but Softrak's Sales Analysis does not track the serial numbers sold to a customer.