Unfortunately if you are using a Business pack SEP 11.0 that would not need any license file for activation you will not be able to get the total number for clients that has the SEP 11.0

Remember: To install only your SEP to the number for Quantity license you had purchase to eliminate conflict and being out of compliance.

There is no concept of license in SEP 11.0

So you don't need to install and licenses and also there is no place to create report on the total number of used client licenses for SEP 11.0.

http://service1.symantec.com/support/ent-security.nsf/854fa02b4f5013678825731a007d06af/1045d9e1cee1b0ff882573a8005e33fd?OpenDocument

waht do you mean exact SEP client installed?

If you want know the total no of pcs which
is installed and connected to server you can get it from Reports--->computer
status-->client online status .For the no. of total client licenses
available for you refer your purchase order

Thank you all for your responses so far but I am a bit confused.

So, are you saying that the only way I can know if i need more licenses, is to do a physical count of computers on which I have SEP installed, check the total quantity I have on the certificate and then determine if i have reached the limit?

I hope to hear from you soon.

Yes you are right