Do I have to write the phone number in a specific format to use DIAL|IT?
You should use the standard ACT fuction; i.e.use the button to define the country (if the country field is filled with the right country the country code will be predefined) you can use () – without any problems but you should not use and
you should use the leading 0 if appropriate i.e.  089 454 6170 the stuff in the  is not seen and it must be the act function that you see by pressing the button on the right side of the phone field.
 010 47 00 47 fine
 (010) 47 00 47 fine
 010 4700-47 fine
 10 47 00 47 would cause issues in Germany, not sure if it works somewhere else