In MDT 2012 same as MDT 2010, here’s a simple way to change the “IT Organization” default text in the Task Sequence dialog box.
In order to change the default text “IT Organization” locate the customsettings.ini in your deployment share folder, it should be in the DeploymentShare\Control.
Right click on the CustomSettings.ini and click on Edit.
Add the _SMSTSORGNAME= string and assign a variable to it and save the customsettings.ini.
In the Deployment Workbench update the deployment share and you’re all set.