IT Works \:\) !! Thanks
i used
$Result = "532|"
$ReturnCode = WRITEVALUE( "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002BE10318}\0006\0" , "IsdnMultiSubscriberNumbers", $Result , "REG_MULTI_SZ")

and now its exactly what i was looking for.

Thanks a lot !!

i have to chance it on many computer
i hope the classes ({4D36E972-E325-11CE-BFC1-08002BE10318})are all the same.
if it isnt cann i go an other way to chance it?

thanks