Once the variable is set, the next step is to ensure it's set.
For that, type:
./directadmin c | grep ^name=
to ensure you see the value specified.
If you do not see the value set, then make sure the end of the directadmin.conf has a trailing newline character.
What this means is that there should be a blank line at the bottom of the file, because when reading a config file, DA defines a "line" has ending with a newline character (the 'enter' key).
Last step is to restart DA to load in your setting:
echo "action=directadmin&value=restart" >> data/task.queue; ./dataskq d2000