calibre 0.6.39 provides three options for how author_sort is computed from author. Using one of these options may help you get what you want.
1) As it always has been. Author is assumed to be in FN LN format, and author_sort is set to LN, FN
2) Copy author to author_sort without modification. This is useful for those who always enter authors and LN, FN
3) A combination of 1 and 2. Use #2 if there is a comma in the name, otherwise use #1.
You control the method using calibre's new 'tweaks' feature. There will be a file in your calibre working folder called tweaks.py. Where this is depends on your system and version. For me, using Windows 7, it is here
Code:
"C:\Users\charles\AppData\Roaming\calibre\tweaks.py"
Change the value of the variable author_sort_copy_method to the value indicated by the comments. Make sure it stays quoted.
The default behavior is #1. If you change the variable to something other than indicated in the comments, the behavior will remain the default.
If the author_sort_copy_method and associated comments are not already in the tweaks.py file, see 'resources/default_tweaks.py' in your calibre installation directory for this information.