Specify filter for method getVariantSelections

Hi there,
or: Dear Oxid-Pros,

The method (found in \application\models\oxarticle.php)

public function getVariantSelections($aFilterIds = null, $sActVariantId = null, $iLimit = 0)

is documented with

Returns variants selections lists array
@param array  $aFilterIds    ids of active selections [optional]
@param string $sActVariantId active variant id [optional]
@param int    $iLimit        limit variant lists count (if non zero, return limited number of multidimensional variant selections)
@return array

Is there anybody out there who can explain how to use the parameter $aFilterIds?
How can I specify a filter and which filters are applicable?

Thank you very much for any hint in advance.