Hello, Guido!
Good topic! I am Dutch and I have all of Vermeulen's (seven) symphonies, the first 5 of which I know quite well. After having borrowed them from the library a few times, I bought them (quite recently) from an online shop here in The Netherlands. I don't have his chamber music yet, but that's something I hope to redress quite soon.
As you say - a fascinating composer. His First symphony, to me, is one of the Best Firsts ever, a glowing, glorious work by a visionary young man. But the Second surpasses it easily - it's driven, barbaric, eruptive. Vermeulen is a very un-Dutch composer: there is no reserve, no sobriety, the music is lava, and it hits you.
Vermeulen is also a great writer about music. His enthusiasm is infectious. It's a pity none of his articles and essays have been translated into English. The way he characterizes Beethoven, for instance, is so perceptive and affectionate, you immediately want to hear his music.
Yes, I really have much time for Vermeulen.
Johan
PS Just saw this: "He has two works on this Concertgebouw Anthology (1950-1960) , his Symphony No. 2 ("Prélude à la nouvelle journée") and De vliegende Hollander: Passacaille et Cortège."
The 'Vliegende Hollander' music is incidental music for a play by a leading Dutch poet. It's a very exciting and grand piece. Do listen to it, and see what you make of it, Bruce.