In the situation described by the OP I'd first stop descent at current altitude and ask ATC for further instructions. in ANY a/c, not only Airbus.
As for the Bus specificalities:
- if I were to discontinue the approach before extending flaps I'd just go for HDG mode laterally and VS vertically.
- after extending flaps - TOGA, then immediately back to CLB detent (to force the FMGS into G/A phase) and "push to level off" to stop climb. Then either NAV to follow Missed App routing or HDG for vectos. Vertically VS to whatever altiitude agreed with ATC.
Last edited by Stuck_in_an_ATR; 1st Nov 2012 at 12:53.