The use of 37 (and possibly 47 mm) Rheinmetall pak was the subject of some previous discussions (both in Dutch):
http://www.grebbeberg.nl/forum/forum.php?item=5012&group=1&view=all (where I erroneously mentioned two guns being bought instead of 2*2 = 4)
http://www.twenot-forums.nl/viewtopic.php?t=1647
I have never seen any documents related to 47 mm Rheinmetall guns being bought by the Dutch.