Here is what’s needed.

3) Improve VPN performance by allowing 6 connections
a. To configure IE8’s HTTP/1.1 connections to use 6 persistent connections per server:
b. Key: \SOFTWARE\Microsoft\Internet Explorer\MAIN\FeatureControl\FEATURE_MAXCONNECTIONSPERSERVER
c. Value: iexplore.exe
d. Type: REG_DWORD
e. Data: 6
f.
g. To configure IE8’s HTTP/1.0 connections to use 6 persistent connections per server:
h. Key: \SOFTWARE\Microsoft\Internet Explorer\MAIN\FeatureControl\FEATURE_MAXCONNECTIONSPER1_0SERVER
i. Value: iexplore.exe
j. Type: REG_DWORD
k. Data: 6

I am pretty sure that you can stop the reduction of ports on a slow connection by overwriting the values with the steps from http://support.microsoft.com/default.aspx/kb/282402

If not with the local reg values — perhaps with the Group policy option as it specifically call out http 1.0

Unfortunately I do not have access to a VPN connection / nor Dialup that I can test with.

Are you able to confirm and potentially add an extra solution to the blog?

Thanks,

HP