Centralised WordPress

Dear support,

Let me start by saying your tool is absoultly AWESOME!!!
I have worpress installed on a windows server Running IIS7

I run several sites on this server and each one of them has the wordpress blog.

To simplify worpdress installations I have done the following:
Each site has a Virtual Directory to a blog centralized folder.

Folder structure
c:\inetpub\blog
c:\inetpub\site1
c:\inetpub\site1\wp-content
c:\inetpub\site2
c:\inetpub\site2\wp-content
c:\inetpub\site3
c:\inetpub\site3\wp-content

http://site1/blog(Virtual Directory to c:\inetpub\blog)
http://site1/mywp-content
http://site2/blog(Virtual Directory to c:\inetpub\blog)
http://site2/mywp-content
http://site3/blog(Virtual Directory to c:\inetpub\blog)
http://site3/mywp-content

W3 cache creates the files and folders correctly in mywp-conent
but when displaying the blog it uses the following links to retreive the minified content
http://site1/blog/mywp-content/w3tc/min/index.php?…
instead of
http://site1/mywp-content/w3tc/min/index.php?…

I know this is an unusual setup and as wordpress allows you to modify the location on the wp-config for the wp-content folder was wondering if anyone could help me resolve this issue.

Regards,

Serg