Having read the Dutch AIP entry, it appears that Soesterberg is not available to civil aircraft.
However, it puts Breda (Gilze-Rijen), into the same category as Eindhoven and Enschede, of requiring permission (0700-1545 Mon-Fri). Eindhoven has operated for many years as a very civil military base. So I'm kind of surprised that you got that reaction to the request to use Breda. Have you tried recently? Tel 0161 296911 given.