pl\sql concurrent program - how to generate zip as result of request?

Oracle Applications 12.1

I can generate zip file in pl\sql as BLOB into conc. request

then save this blob to /usr/tmp/o[numbers].tmp

and concurrent manager takes this file as usual conc.request result and show it when I press "Show result" button in "Concurrent Requests" form.

But, as i have understood, concurrent manager process this file as text (not binary) file, thats why I get only first part of BLOB till first zero byte.

So, I generate blob with 765 bytes size and save it into /usr/tmp/o[numbers].tmp

but after conc. request completing, file $APPLCSF/out/[conc_id].out file size is 5 bytes, becouse 6-ths byte in file /usr/tmp/o[numbers].tmp is "00"