The only way for a Jenkins user to TAG a build in SVN is having configuration rights, if not the user even if has the "TAG" access can not select the credential (even if the user has all access to credentials).

I Think this is a bug because the developers should manage the svn but no the configuration of where to deploy or how is whe job configured.

In previous version of Jenkins/SVN Plugin the credentials for taggin were the same of the developement source and work just fine.