It's enough to have this method in your [Module]Search.php class. If you need to call in the new place then syntax will look like:

bx_import($sClassSearchResult, $this->_aModule);

$sClass = $this->_aModule['class_prefix'] . $sClassSearchResult;

$o = new $sClass($sMode, $aParams);

where $sClassSearchResult - the name of your module Search class.