integrate DHL Online Frankierung API after ordered a specific product (virtuemart, joomla)

I need to integrate the "DHL Online Frankierung API" into my joomla virtuemart. I offer my customers ecu repair services (they buy an repair, send ecu to me and i send it back). to make these process easy for my customers i want to redirect them to a prefilled DHL shippment label (receiver adress prefilled), they only need to input there senders adress and pay directly to dhl. After that the api need to send me the shippmentnumber to ensure quickly delivery to me.