Batch determination

Hi

We r using automatic batch determination sort is based on FEFO(first exp first out) for components..After releasing the order if i want to change the order qty it is creating the new line for each component(Since during release batch determination have been carried out) for additional qty if i determine batches manualy system is not proposing any batch for copms which is having only one batch that is already assigned to the same order which is not issued yet...And we can't change any comp and qty here(as per clien't req we are using user exit)..

Here the existing batch is having enough stock..once i issue the Final then that batch is picked by the system..

Is there anyway to sort out....

Thanks

Gopi