Can't get directional sound working

The soundsource is always omnidirectional, no matter how i define the sound direction and cone-angle sad

I want to simulate a worldspace fixed directional sound.

I use one of the latest svn snapshops, compiled for WinXP
The updating of the sound is done as follows:

Code:

csVector3 worldPos(70.0f, 20.0f, -3.3f);
csVector3 pos = view->GetCamera ()->GetTransform ().Other2This (worldPos);
sndsource3d->SetPosition (pos); // sndsource3d is a iSndSysSourceSoftware3D interface
csVector3 worldDir(0.0f, 0.0f, -1.0f);
pos = view->GetCamera ()->GetTransform ().Other2ThisRelative (worldDir);
sndsource3d->SetDirection (pos);
sndsource3d->SetDirectionalRadiation (3.14f/20.0f);

The position is updated properly, only the directional part does't work

Another thing i noticed is that the sound is not "muted" when the distance of the sound is larger than the distance specified with sndsource3d::SetMaximumDistance()

comment from ss_source.h:

Code:

/**
* Set the greatest distance from a sound at which the sound can be heard.
* If the distance to a listener is above this threshold, it will not be
* mixed into the output buffer at all. This saves a tiny bit of processing.
*/

Another comment in ss_source.h says:

Code:

/**
* Set the greatest distance from a sound at which the sound plays at full
* amplitude.
* When a listener is closer than this distance, the amplitude is the volume
* of the sound.
* When a listener is further than this distance, the amplitude follows the
* formula V = (volume / ((distance/minimum_distance) ^ rolloff_factor))
*/
virtual void SetMinimumDistance (float distance) = 0;

This seems to work, however I can't find a method to change the rolloff_factor sad

does anyone know how to do these things right?
Rick