Porting attachment URLs

I am porting from a moinmoin tarball of the data directory to a live
MediaWiki installation. I am trying to preserve the URLs despite the
intended switch in the wiki engine. Maintaining the page URLs seems easy
enough (except perhaps for some using non-ASCII characters in the name).
However, I notice that moinmoin attachments have URLs of the form:

<wikipath>/PageName?action=AttachFile&do=get&target=attachment.ext

In this case there is no obvious way for me to preserve this URL when
the attachment is moved to a MediaWiki server. I propose therefore to
map all such URLs to the following MediaWiki-friendly form:

<Wikipath>/PageName/Attachments/attachment.ext

and include in the MediaWiki's 404 response page a message to explain
the mapping, in case anyone is looking for the URL to the attachment. In
theory I could automate this response so that an appropriate redirect is
executed, but right now I'm not keen to manipulate the MediaWiki code.

Does anyone have any comment on this strategy?

---Rotan.