How to made level with start pos?

[minami]

Working only in 2.1 version (2.1+ Doesn't work).
1. Build level.
2. Set a start pos
3. Click on start pos > Edit Group > High detail.
4. Now save and exit > Low Detail on .
5. Complete level.
6. Public your level
Now who don't have a access to copy level can't complete level with LDM.
Thx for read.