How to change the default dateformat?

My Sql Server connection has default dateformat to "ymd".
I have to change the dateformat to "dmy" each time when I insert or
update a datetime table column e.g.with '31.12.2005' using the
"set dateformat dmy" command. Does anybody know, how to change the
default dateformat to avoid to perform the set dateformat on
each connection?
thanks
LiborLook here:
You can change the settings of the server, but if yor provider will
change the settings during the login process and sets it back to the
default language settings of the user you have to convert the date in a
explicit format or change the codepage of the user:
http://groups.google.de/group/microsoft.public.sqlserver.programming/browse_frm/thread/6496fbdbbd4cffd9/952557646f8b9a9b?lnk=st&q=serversettings+date+format&rnum=1&hl=en#952557646f8b9a9b
http://groups.google.de/group/microsoft.public.sqlserver.server/browse_frm/thread/6f543ebd963f6e20/46144e7348a7b6ff?lnk=st&q=%22Jens+Suessmeyer%22+boss+tibor&rnum=1&hl=en#46144e7348a7b6ff
HTH, Jens Suessmeyer.