In fact i would allow the flaps to auto retract and then press EXP to maintain S speed.
I would not recommend that, you will potentially trigger the TCAS and you are also running the risk of busting low level/altitude climb restrictions.
As mentioned before by a couple of people:
It is safe to fly between VLS and VMAX (VMO, VLE, VFE).
Select Flap 0 below S speed while accelerating, I can't see anything wrong with this technique.