Playing one of the Instant Action missions on Caucuses, I don't seem to be able to set a Steerpoint as my SPI. It starts out that way, but after firing at a few targets, the TGP becomes my SOI and is generating my SPI.
From there, if I set my Hud to SOI and do TMS Aft Long to set my SPI as Steerpoint, nothing happens.
Have I missed something?