vector SIT_POS = <0.0, 0.0, 1.0>;
rotation SIT_ROT = ZERO_ROTATION;

vector TARGET_POS = <0.0, 0.0, 2.0>;

default
{
state_entry()

changed(integer changes)
{
if ((changes & CHANGED_LINK) && llAvatarOnSitTarget() != NULL_KEY)

}
}

I make a simple test to do, that create 3 box in a line, with center become the root prim and have this script:

default
{
state_entry()

touch_start(integer total_number)

}

The left and right box have name:
<.0,1.0,.0>
and
<.0,-1.0,.0>

So with the script when I was sit on the center box, and touch the left or right box should moved and rotated.
It work fine on regular sims (non Havok4) and some of Havok4. But not on some Havok4 even with same version of the sims server of the Havok4 sims.
After upgrade today, I was check again, and the problem havok4 sims, still failed do the task.

My specific test:
vector cur_pos = <0,0,0>;
vector z_offset = <0,0,0.5>;
default
{
touch_start(integer total_number)

}

I tried this script in a single prim, a root prim (with 1 and with 7 children), and in a child prim. It worked in all cases. I was a little surprised to find that llGetObjectPrimCount didn't include the agent but llGetnumberOfPrims did. That seems to match the havok1 behavior though and I suppose is useful specifically for cases like this - determining how many people are sitting on the object.