How to fold code with regex in NOTEPAD++ UDL v.2.1.0.12

Question

I'm adding a UDL for my special formatted test script in NOTEPAD++. I'm trying to add folding to the code but it does not respond as expected. My code's pattern is similar to XML format, something like that:

[TEST DEFINITION]
    ...
[/TEST DEFINITION]

[TEST STEPS]
    [STEP 10]
        [STEP DEFINITION]
        ....
        [/STEP DEFINITION]
    [/STEP 10]

    [STEP 20]
        [STEP DEFINITION]
        ....
        [/STEP DEFINITION]
    [/STEP 20]
[/TEST STEPS]

I have tried putting:
[STEP (DEFINITION,\d*)]
for "Folding in code 1 style" -> "Open" input and

[/STEP ([DEFINITION,\d*)]
for "Folding in code 1 style" -> "Close" input.

But editor does not fold as expected instead it folds like random lines (or i do not understand the pattern it folds).
Any help?