The Cubase default sample rate is 44.1 kHz so when a new project is created it will automatically change the sample rate of the GS-R24 in the control panel to 44.1 kHz.

If you want to work on a project using a sample rate of 48, 88.2 or 96 kHz:

Open Cubase, create a new project, from the Project Tab go to the Project Setup and set the Sample rate as required, if you then save the project whenever it is reopened it will automatically set the GS-R24 control panel to the sample rate that's been set.

It is also possible to create a default project that can be saved as a template so every time a new project is started you do not need to adjust the sample rate settings, to do this:

Create a new project, set the sample rate as required then from the File tab, select the 'Save as Template' option. You can then create as many different Templates as you require and these can be named uniquely depending on the type of project you are working on.