There's no way this value "Can't be edited", it's defined somewhere, either whoever told you that doesn't know Sourcepawn or doesn't know where to find it.
Edit: If you're using a version of the official VSH build, it's defined in: scripting/modules/handler.sp
Line 1260:
base.ClimbWall(weapon, g_vsh2.m_hCvars.SniperClimbVelocity.FloatValue, 15.0, true);
I presume a compilation of the main VSH plugin would be required to put it into effect.
There's no way this value "Can't be edited", it's defined somewhere, either whoever told you that doesn't know Sourcepawn or doesn't know where to find it.
Edit: If you're using a version of the official VSH build, it's defined in: scripting/modules/handler.sp
Line 1260:
base.ClimbWall(weapon, g_vsh2.m_hCvars.SniperClimbVelocity.FloatValue, 15.0, true);
I presume a compilation of the main VSH plugin would be required to put it into effect.