1. The property  name is case sensitive - old MS KB documents contain bad
property name
2. Which tool did you use to add the property? I didn't manage to set the
property properly with other tools than plex.

1. The property  name I used is
urn:schemas-microsft-com:publishing:ServerURL, I typed it in exactly as the
article said. I got it from that sps extranet article  page 12!
2. The tool I used was the exchange explorer  tool it said use the WSS
SDK but the link pointed me to the Exchange resource kit that has an
explorer in and as SPS is based on the exchange store thought it must be ok
to use that. When you say you had problems  setting the property what errors
did you have? I followed the article and I could see the entry in the detail
view as a new entry.
3. When it says Value e. g. http://NetBIOS_name
<http://netbios_name/> is that a variable it uses or do you put your
machine name there? Have tried both ways but no joy.

Here's what works for me:

Name: urn:schemas-microsoft-com:publishing:ServerUrl (Notice Case here!)
Datatype: string
Value: fully.qualified.domain.name.of.the.server.here

Check out microsofts KB (Q296602) at:
support.microsoft.com/default.aspx