Brongers mentions the aircraft Montana means as an 8./KG 54 aircraft.
This is the entry on his website:
http://home.deds.nl/~bhummel/gif/duitseverliezen.html
7) 12 mei: He-111P van 8/KG 54 neergestort bij OOSTBURG; 1 man, Ogefr Emil Luis aldaar begr; thans Ystn graf CG-124.
-Ystn
7) may 12th 1940: He-111P of 8./KG 54 crashed at Oostburg, 1 man, Ogefr Emil Luis burried there, at the moment Ystn grave CG-124
This was an 8./KG 54 aircraft, not a 1,4 or 7 staffel aircraft