Hey Stefaan,
With the help of Olivier Dony, I've managed to configure it on a new VM. Problem is that accouting modules and data have to be
uninstalled/removed.
1. if accounting modules are installed: uninstall all accounting modules (dutch: boekhouding, boekhouding en financiën) -> all data will be
lost !!!
2. install nl_BE as supported language (Flemmish (BE)/ Vlaams (BE) )
3. set nl_BE as default language for the administrator
4. install the module 'België - Boekhouding' (l10n_be)
select: 'belgië - boekhouding'
select: 'PCMN'
accept the other options and finish the installation of the module
5. install the module "Boekhouding en financiën"
6. et voila ... there they are!