I have one router Cisco 7204 con IOS 12.4(15)T3, with the service SLB configure on it.
I need to know if the Cisco 7204 support NAT source and what IOS version I need for support this feature.
So you are searching for client NAT in SLB. Well according to Feature Navigator none of the 12.4T train support that feature. 12.2SB does support client NAT but you will need to use Feature Navigator yourself because if you need to make sure that the IOS version you choose not only supports SLB client NAT but also all the other features you are currently using on your router -