I found a solution to my problem without need to run JavaScript when PDF-File is opened.
In case somebody need this, DateTime-Picker can be added to the PDF-Document using the following annotation. It basically adds script 'AFDate_FormatEx("dd.mm.yyyy")' for 'Format' and 'Keystroke' actions.
/AA <<
/F <<
/JS (AFDate_FormatEx\("dd.mm.yyyy"\))
/S /JavaScript
>>
/K <<
/JS (AFDate_FormatEx\("dd.mm.yyyy"\))
/S /JavaScript
>>
>>