Yes, you should be able to achieve what you want to do, however, I'm not sure exactly what you're redirecting.

If you have oldsite.com/directoryname

and you want that to redirect to:

newsite.com/tabid/451/default.aspx

then you're not really using the full potential of the module.  The module will give you friendly urls, so you don't need to have a url of tabid/451/default.aspx, you should instead have a Url of newsite.com/newpagename.aspx

Now, if the previous Url was a directory, then you'll probably have to switch on the 'wildcard' extensions for IIS so that requests for old, directory based urls, will work correctly.  If this isn't the case (ie, it was really oldsite.com/directoryname/pagename.htm or something) you'll still need to make sure the the asp.net runtime is mapped in IIS to handle the page type of your old site (be it .htm, .asp, .php etc).  This is done in the IIS configuration for your site.

To redirect one domain name to another, you'll have to (1) set up the old domain name as a portal alias in your site as well as the new site and (2) add in the following attribute to the 'DNNFriendlyUrl' in the web.config file : usePortalAlias="0,www.newsite.com".  This will redirect the old domain name to the new domain name.  Of course, you'll have to make sure that the DNS entries for your old domain name point traffic at the site as well.

Hope this helps?

Bruce

Wildcard extensions are applied to the entire site, you can't just apply them to one or two Urls.  However, if you enable wildcard extensions in IIS, you should be able to set up urls like you wish.  This site runs on wildcard extensions with extensionless Urls.