What certificates does EJBCA support?
EJBCA support X.509 v3 certificates and CVC certificates according to EAC 1.11 (BSI TR-03110).
Does EJBCA support Netscape certificate extensions?
Yes. through custom extensions, see the documentation about certificate extensions. These extensions are old and should not be used. There are no common clients that needs them anymore and it is almost certain to cause you more trouble than they solve. Please don't use them.
Does EJBCA support Microsoft certificate extensions?
Yes, through custom extensions, see the documentation about certificate extensions. Many MS extended key usages are supported and all common (all we know at least) windows functions using certificates works with EJBCA certificates.