using rundll32 user32.dll to indicate that a user's environment has changed.

Question

I do not have the ability to modify environement variables in windows 7. However I have been granted permission to modify the registry settings. So for example I can modify: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment Key: BPATH which is appended to the end of my System's pathEnv.

but when I make the changes the change does not take affect until the next reboot.

I would like to find a command line that is "Alwasy Installed" that can signal a change in BPATH such that "PATH" is always updated for subsequent programs and windows.

rundll user32.dll, [ BroadcastSystemMessage PATH CHANTGED... or somehting...]

Conditions:

1. I can only edit the path and bpath via the registry, not from the System, Advanced tab...
2. I do not want to install any software that is not part of a standard out of the box windows 7 install.
3. Typically this should just be done from the CMD prompt of the PowerShell prompt.