setting a different default member based on the perspective?

Hi,

I want to set a different default member on 1 dimension regarding the perspective used by the user.

in management studio, I can run this:

alter cube [Perspective] update dimension [dim].[hierarchy],DEFAULT_MEMBER = [dim].[hierarchy].&[1];

then any select statement in the same session used the default member just selected.

But now I try to make this a default for all the sessions.

So I create a personalization  extension to push the later statement, but I receive this error:

Parser: The statement is not supported by this interface.

(I'm using the sample extension created by microsoft)

is there any other way to setup the default member for each perspective?

is the personalization extension the way to go? and how to support the alter cube ... update dimension?

thanks.