multiple Vlans trought WS500

No, it doesn't do VLANs. Also, it is not a good idea to put the appliance between the switch and the ASA like that if you want the ASA to inspect all the vlans. Instead, use WCCP. That way the ASA can pass the web traffic to the WS500 on a per connection basis and the ASA is handling all the VLAN information.

http://wsa.sophos.com/docs/wsa/cg/pdf/swa_cg.pdf

Thank you,

If i want to use WCCP, the appliance must be in the same subnet as ASA (mean the gateway)? Ans is it possible to use wccp for multiple vlen

There is two options available for config - L2 and GRE

If you do L2, it has to be the same subnet

If you do GRE it can route through other L3 devices to the ASA

You can find all the information needed in the Web Appliances UI: 

config > network > WCCP 

Then click on Help in the top ribbon

There is two options available for config - L2 and GRE

If you do L2, it has to be the same subnet

If you do GRE it can route through other L3 devices to the ASA

You can find all the information needed in the Web Appliances UI: 

config > network > WCCP 

Then click on Help in the top ribbon