[gwnn]

AJxx
Axxx
Jx
Qxx

p opens 2S v at imps (5 spades, 4+ m, weak but p is conservative). You can bid:
-2NT (3S over his 3m is NF)
-3D inv+ with spades
-3S
-4S

[Zelandakh]

Over my 2♠ Muiderberg this would be a weak (3♠) bid even though 4 would make on a perfecto. Opposite a conservative enough partner it would move up to a 3♦ response. 2NT will not tell us what we really want to know so I do not see the advantage of going that route. As an aside, I think it is better to invert the 3♦ and 3♥ responses to a Muiderberg 2♠ opening; then 3♦ shows hearts and 3♥ is the good raise.

[gwnn]

Zelandakh, on 2012-November-30, 02:52, said:

As an aside, I think it is better to invert the 3♦ and 3♥ responses to a Muiderberg 2♠ opening; then 3♦ shows hearts and 3♥ is the good raise.

It is true, but usually if I propose such a change in the system one of two things will happen: partner will reject or he accepts and forgets.