it is in there, just not with enough info probably. just did some tests
Code:
2010-10-29 07:51:53,038 INFO [btpool0-13://iccarus.test.com:7071/service/admin/soap/CreateAccountRequest] [name=admin@test.com;mid=2;ip=192.168.93.2;ua=ZimbraWebClient - SAF3 (Linux);] soap - CreateAccountRequest
2010-10-29 07:56:19,649 INFO [btpool0-0://iccarus.test.com:7071/service/admin/soap/SetPasswordRequest] [name=admin@test.com;mid=2;ip=192.168.93.2;ua=ZimbraWebClient - SAF3 (Linux);] misc - delegated access: doc=SetPassword, authenticated account=admin@test.com, target account=testadd@test.com
2010-10-29 07:55:06,904 INFO [btpool0-0://iccarus.test.com:7071/service/admin/soap/DeleteAccountRequest] [name=admin@test.com;mid=2;ip=192.168.93.2;ua=ZimbraWebClient - SAF3 (Linux);] misc - delegated access: doc=DeleteAccount, authenticated account=admin@test.com, target account=testadd@test.com