Just looking at the URL-Rewrite module with a plan to POC wordpress MU and came accross a few things 1st being the rule import does not like "RewriteBase BASE/" saying it is not supported, Great, but it woudl be nice I could then manualy edit the generated XML rule set, so I can apply them...

Looks like this is a bug in the rule import tool. Thanks for reporting this - good catch!

The reason why the appendQueryString is set to true is because its semantics in IIS is somewhat different from QSA in mod_rewrite. In mod_rewrite if substitution string does not contain query string then the original query string is preserved regardless of QSA flag. For example this rewrite rule: rewriterule...

The "L" flag stands for "Last rule", meaning that if this rule was evaluated successfully then no subsequent rules will be evaluated. In URL rewrite module we have a rule attribute called "stopProcessing", which has the same semantics as L flag in mod_rewrite. The rule converter...