Hi -
Umbraco 4.8.0 is in the testing queue at Microsoft for release to the web feed. At the time 4.8.0 os released to the feed, the v5 package will be retired. I think, but don't know for certain, that the additional overhead of testing app packages
for WAWS has overwhelmed the Microsoft team.
For now, you can create an empty web site, then deploy the Umbraco 4.8.0 web app form your local machine using the publishing tools in WebMatrix, then run through the Umbraco installer to setup your Umbraco site.
With WAWS there is no concept of affinity groups. As the underlying framework (Antares) runs in the same cloud service, it essentially IS in an affinity group already.
Hope this helps.
-Paul