Hello Jānis,
the easiest way to extract the part of the date is to use the platform's method Format like this
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Prefix = Format(YourVariableContainingTheDate,"DF=ddMM") |
How to apply the extracted prefix to the number? - it depends on the solution you use.
In the abstract solution there should be document's event
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Procedure OnSetNewNumber(StandardProcessing, Prefix) |
where you can pass your prefix