solved my own problem: installed MSDOS 6.22 which can be found on the web. It comes with three images of floppy's. In VMware you can define a virtual floppy on the base of an image. Couple the image of the first disk to the floppy, run the setup. When it asks for the second disk just link the second image to the floppy etc. Then I installed oakcdrom.sys the same way in order to have MSDOS read CDRom's. From there DOS 7.1 can be installed.
New problem arose when configuring sound. That one I did not resolve as of yet. Who has a clue?