Hi EIU,
according to the FCOM :
To interrupt the approach, or to perform a go-around, from an intermediate altitude in the approach,
and if TOGA thrust is not required, proceed as follows :
SET the thrust levers to TOGA detent, then retard the thrust levers as required.
This enables to engage the GO-AROUND phase, with associated AP/FD modes.
SELECT the applicable AP/FD and A/THR modes on the FCU.
Note: If the thrust levers are not set briefly to TOGA detent, the FMS does not engage the
GO-AROUND phase, and flying over, or close to the airport (less than 7 nm) will sequence the destination waypoint in the F-PLN.
Now the associated AP/FD modes are, always according to the FCOM : Setting at least one thrust lever to the TOGA detent engages both SRS/GA TRK modes, if:
‐ The flaps lever is at least in position 1, and
‐ The aircraft is in flight, or
‐ The aircraft has been on ground for less than 30 s (AP disengages and can be re-engaged 5 s Which is our scenario.
For what concerns the disengagement conditions the FCOM states :
The SRS mode disengages:
‐ Automatically, at the go-around acceleration altitude (GA ACC ALT), or if ALT* or ALT CST* mode
engages (above 400 ft RA)
‐ If the flight crew engages another vertical mode
‐ If the flight crew selects a speed while in SRS mode: SRS reverts to OP CLB mode and a
triple-click aural warning is heard.
As you mentioned we are above the go-around acceleration altitude, so the airplane doesn't have a target altitude to level off. It will thus remain in SRS. Another input for this condition can be read from the explanation of the SRS system which adds a note : Note: If during takeoff the flight crew inadvertently sets an altitude on the FCU below the
current altitude, the aircraft will remain in SRS mode until the flight crew takes some other action. Basically you can just push v/s 0.
That's only to mention the book explanation, pilot techniques are obviously personal and all inputs are welcome !