How to automate custom imports?

Hi there, I’m looking for a way to schedule some custom import jobs within Axapta. It seems like the drop down menu to select the definition group on the import form filters out the custom definition groups. Is there anyone who know the best way to automate that kind of process? Is there any other interface that allow to do this or should I call it from code, if yes what classes should i look to? I’d really appreciate any clue on the topic. Thanks in advance.