Using the SAVE RECORD command to save a 4D Write document into a BLOB field (e.g. "WriteArea_") does not automatically save the record the way the ACCEPT command does. The reason is because the SAVE RECORD command doesn't honor the automatic relation between the TABLE]WriteArea_ field and the WriteArea area the way the ACCEPT command does. You need to procedurally assign the content of the Area to the field before executing the SAVE RECORD command.
[TABLE]WriteArea_:=WR AREA TO BLOB(WriteArea;1)