> Unfortunately it 
> mirrors the site ok, but it changes the file name 
e.g. 
> default.asp?ID=42 end up being default69ca.asp how 
can 
> I maintain the parameters?
The engine always rename duplicate documents, that is, 
if index.html?id=1 and index.html?id=2 are downloaded, 
this will generate index.html and index-2.html on the 
local filesystem. The collision system requires some 
CPU, and therefore having MANY URLs with identical 
path may result in a ressource hog. This is why, by 
default, the engine will append on all files built 
using an URL with query string, a hash hexa number 
(example: c4d0). Therefore, index.html?id=1 and 
index.html?id=2 will generate something like 
index1d5a.html and index78f8.html.

You can change this behaviour using the user-defined 
structure:

try the option below:
-N "%h%p/%n%[id].%t"

This option will name all pages using the ID parameter 
(if any found in the query string) appened in the 
filenames.
In this case, index.html?id=1 and index.html?id=2 will 
be named <path>/index1.html and <path>/index2.html

But remember that, if a collision is found, the engine 
will always rename the final file. Therefore, 
index.html?id=1&page=1 and index.html?id=1&page=2 may 
be named locally index1.html and index1-2.html, 
because the passed user-defined structure has 
generated a collision.