Hello,
I do not believe that the DLP Standard version supports custom DI's. The Standard version is a stripped down version of the DLP platform, if you do not see the option of a "Custom Data Identifier" under the Manage section it may not be there.
The option of the Custom Data Identifier is available in the Full Version of 11.1
Also when doing a DI use /d{3} not /d/d/d
Your best bet is to look at othe DI examples and try to find similar expressions.
Attached is athe Admin guide, look to pages 460 and it will outline how to create them.
Hope this makes sense.
If this solves your questions please marked as solved.
Ronak