A new documentation is available for Squash TM 2.0 and later versions, check it here
It is possible to modify the welcome and login message of Squash TM via two buttons:
[Consult/Modify login message].
[Consult/Modify welcome message].
In the Administration page, click on [Consult/Modify login message].
A rich text editor is displayed in the workspace, by clicking on the text message displayed. You can insert the text and items you want within the limit of the available functions of the toolbar.
The procedure is the same as the one for the login message. In the Administration page, the dedicated button is [Consult/Modify welcome message].