[Typo3] Include loginbox on each page

[mamax]

Hi,

I want my Loginbox to be displayed on each page on my site (it's placed in
the header part).
The point is: my header is defined as part of the HTML template and the
login is a marker inside the header.

How can I define this ###LOGIN### object to refer a certain page (defined in
T3, hence not a file but from the T3 db)?

Max