The simplest way for you to update the big3d agent would be to rediscover the F5 device from the System Center Operations Console and check the 'big3d agent update' check-box at the bottom of the F5 discovery wizard window. And of course the account that you are authenticating with to the F5 device should have enough privileges to perform the update. If you do this, the discovery wizard will upgrade the big3d agent 'transparently' during the device discovery process. Otherwise you still have the manual upgrade option, if you follow the Dev Central article on this topic:
http://devcentral.f5.com/wiki/default.aspx/MgmtPack/Big3dManualUpdate.html