Something along these lines should do the job...
Code:
RewriteEngine On
RewriteCond %{QUERY_STRING} &/(Products/Rigs/milo.htm)$
RewriteRule .* /%1? [R=302]
...obviously that's pretty specific and will only work for a single url, but to make it more generic you just need to replace the /Products/Rigs/milo.htm part with a Regex pattern. I'm not familiar with the URI design for this project, but I would assume that something like this would be suitable...
Code:
RewriteEngine On
RewriteCond %{QUERY_STRING} &/([^&]+\.htm)$
RewriteRule .* /%1? [R=302]