[CentOS] tool to manage a PKI

Hello,

this is a little bit off-topic (even if it have to work on CentOS ;-)

I'm looking for a tool to manage a small Public Key Infrastructure, with 
creation/revocation of certificates X.509, export in PKCS#12 format and 
have the ability to handle CSR (Certificate Signing Request).

I've wrote my own script to perform it (openssl command line based): 
it's a good way to underdstand concepts, but a little bit difficult to 
maintain and extend...

After googling a bit, I found PHPki (http://www.sf.net/projects/phpki/), 
that is nicely web-based (php) but unfortunately, It does not handle CSR.

What tool do you use to manage your PKI ?

Thanks for your comments, clue or advices.

Pierre Bourgin