Where to see the user maintenance activity log (creation,deletion..)?

Hi, SDN Fellows.

This should be a Basis question. But I only able to find this category (Netweaver AS) to write this post.

Our current user management engine is taken the user data source from the ABAP System (CRM system).

I know that I can do the user maintenance tasks through TCode: SU01.

I just wonder where I can see the log for all the user management activities, i.e. 1) User account creation; 2) user account deletion; 3) user profile modification and etc for particular period.

Another question, can I see this activity through portal too? Assuming I am having Super Admin role portal.

Thanks,

Kent