If you have maemo-extras enabled, you are able to install them directly. In application manager they are:

• Pidgin protocol plugin for Office Communicator
• Pidgin protocols plugin for Conversations and Contacts

You don't need to separately install telepathy-haze as it's a dependency of the account-plugin-haze.

You shouldn't need to copy any files from ~/.purple/certificates/x509/tls_peers/ as those are the server certificates and not the certificate authority (CA) certificates. It's also not a recommendable solution. The best way is to use pidgin debug to find out what certificates are necessary
and from there you can see in the output
when pidgin client will ask you for accepting the server's certificate. And these are the certificates you should seek to be available under /usr/share/purple/ca-certs.