Installing PosygreSQL 8.1 on Windows2003 server in terminal session (remote desktop)

Hi,

I try to install PostgreSQL 8.1.3 on Windows2003 server. I have no
phisical access to the server, only through remote desktop. When I run
installer, i get this message:
"The PostgreSQL installer must be run on the system console, not in a
terminal service session".

Is there anything I can do to install using installer, or do I need to
instal POstgresql by hand?
If so (by hand), is there any step-by-step manual describing
installation on windows?

Thanks in advance,
Pawel