I have several mojoPortal sites that have been in Google for over 2 years. Google has never shown a reference to mysite's default.aspx. They always list home.aspx, blog.aspx, about.aspx, etc...
A few days ago, I did attempt to change one of my mojoPortal sites home page reference using the pages "Canonical Url Override" and instantly lost all that pages Google +1's till I removed it. See this post.
BTW in case you did not know - The meta keywords tag is no longer referenced by Google. I'm not sure if the Bing/Yahoo team use it or not.
Google wants... Content, Links, Title, Description, now (+1's), Links, Links, Links as well as 200 other secret ranking indicators. Did I say Links?