SQL Differential Backups

Tech Tip: Click here to run a free scan for Windows Errors and optimize PC performance

In our Maintance plans, we have our full daily backup running fine, and our
Transactions running fine, i.e every 30 minutes.
We can perfrom manual Differential backups fine. We just can not get the
Differential backups to run out of the schuduler.
We're trying to achive, Differentials every 4 hours, with Transactions every
30 minutes inbetween.
Any help will be most appreciated.
.