add new line item in existing outbound delivery

Hi,

I am trying to add new line item in existing outbound delivery with material number and quantity.

for this i tried BAPI_OUTB_DELIVERY_CHANGE and LE_MOB_DELIVERY_UPDATE.

but both fm doesn't work and this will not add new line in that delivery.

please help me how can i add new line item in delivery.

I hope someone will help me........plz

Thanks