An air carrier Captain reports the failure of the push back crew to conform to well established SOP for clearing the aircraft for independent movement.

Narrative

Our push crew used non standard SOP's during our push back last evening that I believe need to be addressed. After I cleared the push crew to disconnect their headset; the tug driver made the comment 'don't worry about the salute; you're good to go.' I wasn't sure I heard what I did; so I asked the tug driver to please repeat what he said. He again said 'don't worry about the salute; you're good to go.' I then told the tug driver that 'it was very important that I receive the proper salute and release from guidance' to which he replied 'OK.' The tug driver then backed the tug straight back (approximately 15 FT) placing the tug directly in front of the airplane while we were given the salute. The salute is one of the most violated SOP's that I witness. I'm not certain that the ground crews understand that once given the salute we can begin our taxi. I'm also not certain that the ground crews understand that in the cockpit; we have restricted visibility to what is underneath the airplane. Obviously; a crew would not purposely begin their taxi knowing the tug is directly in front of them; however; a dimly lit ramp area at night in limited visibility and the normal challenges of keeping the schedule; I can't help but think that a crew might not always notice the stalled tug in front of them.