Thank you for replying.
After all, I gave up the decompression in the engine of DOpus .
I seems to be still impossible.
I decided to use An outside application program .
Then, I found linking useful ahead.
[WinRAR Compress/Decompress Buttons (and other))
according to this,I decided to arrange The button of an external application program
in the toolbar .
Everything went well. Thank you for teaching.