License question to develop webi, crystalreports

Hello,

Need your help to clairfy  BI 4.1 licensing.

Technically,if we have NUL and CSBL, we can connect to BI 4.1 using client tools - Information Design tool, Crystal report for enterprise  and create /edit report.

Do we need to buy separate licenses for creating reports in addition to NUL, CSBL we already had on BI 4.1 server ?

For example, I have 10 developers ( assigned NUL at BI 4.1 Server level) need to create crystal reports  using crystal report enterprise and crystal report 2011 which is installed on citrix server.

I have gone through multiple  documents and it is kind of  confusing.

Thanks in Advance !