Hi Gary,
Typically, if traffic is getting to the webserver and not back to the client there is a return-routing issue. If you go to the pool statistics and you see packets in but 0 in the out column, this is a good indicator of this. This is normally an issue when the F5 is not in the default route from the web server back to your client’s subnet or if your web server, client and load balanced VIP are all on the same VLAN you'll want to turn on SNAT. The traffic has to go back through the F5 on the route back. SNAT can be enabled on the VIP, for your test purposes AutoMap should work.
Let me know if this is not your problem.
John