Need module creation and module logic help

Hello,

i hope my english is understandable:). I have a problem to make an module, and i hope a short description is at the moment okay:).

So i will integrated following function in a module:

automatic download external pics from server and save it with the original name (to the oxid-logik optimized names and db-entrys will follow),

No i have found it in the method _importOne() in exERPBase called from GenImport extends GenImport_Main and so on. Deep in the core.

Now i will put this core-hack (_importOne()) in an extra module and have tried many:

  1. extends the whole object-hierachy to the oxERPBase with ext_oxERPBase extends oxERPBase and ext_oxERPBase will all other calls extends with a ext_ prefix.

  2. Im not going in steps deep in the core with extends , i going directly in the oxNew-Factory created copy and extends this with _parent

class extGenImport extends extGenImport_parent

very cool i can save one step and overwrite the render()-method where i hack the object-creation with

$oErpImport = new ext_oxErpGenImport();

Cool two ways two same problems. In the first Step (NavStep == 1) the exGenImport and the original Object call both the method render() and both give me an debug-ouput with

echo echo get_parent_class ($oErpImport);

this debug-method says me two render()-calls give it from the copy and the orignal

first call the copy: ext_oxErpCsvsecond call the original: ext_oxErpokay its a problem i think the render()-method will be called automatic but i can believe that the oxNew-Factory has called this function?The oxNew-Factory extends the object GenImport and all templates-call from &cl=genimport will be going to the copy. Extends the &cl=extgenimport is not very good:)Okay two functions and i hoped that NavStep = 2 will take the copy-functions and go to the next step and take in NavStep = 2 the ext_oxErpGenImport()-Constructor and notthe original Constructor when he called him. NO:). In NavStep he forget the extends from the oxNew-Factory and call the old original.Can anybody understand me and help me with my problem to hack the core (oxERPBase)??? I dont understand why he takes first my module-extends and overwrite it with original so that the next steps takes the orginal?