How to Insert binary data into table by using controls signature in HWC

In Hybrid Web Container(HWC),

I want to upload data of controls signature into DB Table.

First I created table which has column type binary in sampledb, and MBO.

Next created screen which has controls signature and menuItem to run create operarion.

After deployed these in sup, run application in workflow and wrote signature on this screen.

As a result to run create operation, "NULL" inserted into table.

run operation in not write signature, the column had "0x".

P.S

If binary data is not, Confirmed that data has inserted.

Please advise if there is anyway to accomplish this - Insert binary data into table.

Regards.