I apologize, I thought you were having issues with the SB's and were inquiring "how and why" to delete the SB's.
Enterprise Activation does not require you to send SB's(they are sent by the BES).
Service Books can be categorized into BIS & BES.
When a personal BlackBerry registers with the wireless network, the carrier data package determines the service books sent to your BlackBerry. The BIS service books allow you to do basic functions and includes custom apps and features.
When you purchase a BES plan, you don't receive new SB's but allows you are premitted to perform wireless activation from the BlackBerry. During the activation process, the BES sends an encryption key, IT Policy, and service books. All three are required to communicate with the BES.
Every email account setup will have a service book. Example of different email SB's are:
BES -> Desktop [CMIME]
The BlackBerry requires a [CMIME] Service Book to send email. If you delete a specific [CMIME] SB and then restart the BB...you will not be able to send a message from the BB using that email address.