Tux / apache / squid(?) questions

[lisbon_pt]

Hello

I have a TUX (?) problem, but I would like to share with this community.

browser /cache ----connect---> FRONT END --- possible redirect to BACKENDs
                                                         (1)          
                   (2)

In (1), I have TUX and apache 1.3 with same DOCROOT
so I guess TUX will really accelerate responses for request which
objects are in this DOCROOT.

however if objectas are not in (1), there will be redirected to (several)
backends (IIS 5.0 - with header expires configured for 9 days).

My doubts are (if someone could help - hope I'm not demanding too much):

1. would the answers sent from (2) throught (1) be cached by TUX?
    (TUX doesn't seem to me a cache, but an accelerator for user-space
     web-server, as apache)

2. The solution could be:
    1. have squid as cache in FRONTEND
    2. requests not served by TUX should be redirected to squid
    3. squid would contact BACKENDs (redirect) and will cache answers
        from backend

I really would appreciate any help (I know you all have to do but maybe already
faced same quesions)

kind regards,
lisbon_pt