Flex assets - getChildren - API

Hello guys, we are running WebCenter SItes 11G R1, and we are trying to develop some API code, to get the children of a particular flex asset. So far we have not been able to come up with API code to do this. So far we have been able to accomplish this, using declarative syntax (using the addhancestorconstraint we get all the assets that have a particular one as a parent):

   <searchstate:create name="ss" op="and"/>  
       <searchstate:addhasancestorconstraint    name="ss"   
                                                immediateonly="true"   
                                                assetid='<%=ics.GetVar("categoryId")%>'   
                                                assettype='<%=ics.GetVar("categoryType")%>'    
                                                bucket="ss2" />              
       <assetset:setsearchedassets name="foundProducts" constraint="ss" assettypes="product_C"/>   
       <assetset:getassetlist name="foundProducts" listvarname="productResultList" immediateonly="true"/>  
       <ics:listloop listname="productResultList">  
              …  
              …  
       </ics:listloop>