Alternative Futures
Consider the basis upon which SLA has built its empire. It came about in a time of war that had spread across the known universe like a cancer. SLA was the natural inheritor of this enviroment; they succeed because they fight harder than everyone else. The days of the great wars is passed, and with it the reason for SLA to exist and thrive. So SLA now fights itself, waging war upon it's own people in the name of Progress!
But if you still find it hard to get inspiration form this background then why not consider changing things a little. The following ideas may help....
The last of these ideas is really just using the idea of 'Warp Storms' from WH40K(tm) within the SLA universe. Have Mort cut off by 'Flux Storms' which stop ebon fold ships from travelling. The only goods able to get to Mort would be by ion drive ships, which would slow things down considerably. As Mort is a dead world it is unable to make anything without a constant supply of raw materials. Thus bullets would soon fall into short supply, and dead bodies would be treasured as a food resource. Armour would be scavenged, and power sources jelously guarded. Remember, there is no solar power on Mort.
But inspiration for the SLA universe can be had without such drastic action. Anyone who has watched the X-Files will know how an Ebon investigator feels searching for the truth. Remember, the Internals only have one policy....
Deny Everything!