a addition question about update task

Hi, everybody.

I have ask a question about update task yesterday, do you remeber?

I assign several update/insert actions in a function, and call it in a update task way.

As there are several tables should be deal with, if return an error, how to know which table update/insert is failed in this update task.

it looks like this:

function XXXXX

insert talbeA ....

update tableB .... (if there is an error)

end function.

call function XXXX in update task.

commit work and wait.

if sy-subrc <> 0 .

....

if failed, how can I know the error is due to tableB?

As the function can't return anything in update task mode by parameter, I try some crossing-program mechansim.

I used the Import/export(both ABAP memory and cluster mode), try to use export in funcion to trap(export a flag after every update/insert), and import trap result after commit. when result successful, trap is correct,but when error occur, the import is also null.

Can anyone give me some suggestion, in which way I can get I want. by which technology?

Any suggestion is welcome.

thanks a lot