This tractor rocket configuration was also - kinda - used on the Spartan ABM. The Thiokol TX-239 was a spherical "gas generator," with the exhaust ducted forward and out through for rocket nozzles, each in the trailing edges of the forward fins. Moving the fins vectored the nozzles. I imagine this was thought to simplify the control system, at the expense of weight and some pretty harsh environments for the duct work and rotary joints.
Not sure that's what they're going for with ALASA, but there it is.
Note: I think the illustration below has the gas generator in backwards.