Cisco Firewall :: NAT On ASA 8.2 For Second ISP Connection

I'm working on a problem at the moment where I have 2 Internet connections each with their own Interface on an ASA running 8.2(5). What I want to be able to do is host different web sites on each ISP's ranges but I'm banging my head against a wall at the moment trying to either get the routing or NATing to work in a satisfactory way.
 
The default route is via one of these Internet connections and obviously the website hosted on this Interface is working fine.
 
To get another website hosted on the other ISP or interface - traffic is getting blackholed as it is being routed in the 2nd ISP interface and then trying to be routed back out the 1st ISP interface.
 
I thoguht I could overcome this using Policy Based Routing but ASA does not support this. I'm also aware that I can overcome this problem by upgrading the ASA code to 8.3 or 8.4 where the NAT will overide the Routing table
 
I'm vaguely thinking that there might be a way to overcome this using clever NAT but not been able to figure it out yet. A lot of other Forum posts have sugested that you can use Policy NAT (either Static or Dynamic) or a Dynamic NAT to get the second NAT working and overcome this routing problem but all of these options seem to define a specific source where I need to allow ANY Source on either connection. (Connections inbound to the webservers originating from anywhere on the Internet).
 
I toyed with the idea of Source NAT'ing traffic coming in on the 2nd ISP connection so that it would appear to originate from an IP in the same network. This would overcome the routing problem but not ideal as WebServer logs would see all connections originating from this IP as opposed to the real IP on the Internet.
 
My current (relevant) congfiguration looks something like this:
  
static (DMZ, EXTERNAL_ISP1) 192.168.1.1 10.0.0.1 netmask 255.255.255.255
static (DMZ, EXTERNAL_ISP2) 172.16.100.2 10.0.0.2 netmask 255.255.255.255
!
route EXTERNAL_ISP1 0.0.0.0 0.0.0.0 192.168.1.254 1
  
I would have thought that this is a fairly simple task to achieve but it seems not (at least not on ASA 8.2). I have attached a rough VSD to illustrate what I mean.