HELP!!!!

Help!
I'm hitting a brick wall in trying to write our case statement. The reality is its incredible difficult to evidence need.
We're running loads of statutory contracts and our directors are looking for more opportunities in this area, but I am tasked with starting a programme of unrestricted income generation.
I'm working on a case statement but when I ask questions such as : why do we need more money? what's it for? what are the specific projects this will support? why is it urgent? ...then the answer I keep coming back to is...having unrestricted income is an organisational aspiration and is not based on beneficiary need...
I'm starting to feel like I'm beating my head against a brick wall and working in isolation.
Any advice?