"None" is quite right - I think! Its been a while since I flew 757 but the SOPs catered for a GA from above Missed Approach Alt in the following way if memory serves correctly:
PM Calls "Above Flap Retract Altitude"
PF Calls (Assuming manual flight) "Set Speed Vref 30 +80, Climb Thrust."
You can then select Fl Ch, Hdg Sel, LNav etc as appropriate to comply with the revised clearance.
Modes should all go to GA initially. Thrust for 2000 fpm ROC. FD directs elevators to fly Speed and Ailerons to maintain ground track. Since Elevators are flying speed and Thrust is set for 2000 fpm climb, you will never get an alt cap unless you reset the mcp alt window to above your current altitude or select another pitch mode such as Alt Hold.
Standing by to be corrected.
Now, as to what happens on an early GA when you use VNav for acceleration and there is still an active waypoint such as the OM with an alt constraint (below you) between you and the rwy - well thats another story. Later software mods can remove this problem.
