Let's face it, it's much harder to implement Scrum (or conduct any other form of change) without the support of senior management. If they are not just skeptical but even reluctant, then, yes, you're going to struggle.
This being said, I would like to share the following pieces of advice with you.
#1: Just do it.
Your boss probably trusts you to some extent. How much exactly he trusts you can vary from 1 to 10. But I doubt it is ever at zero -- otherwise you'd be gone by now.
Use this little bit of trust to take initiative. There are many things in Scrum and Agile development that are "low-hanging fruit" and for which I've never seen a big boss get mad at teams:
Planning the team activity on a daily basis (whether you decide to call that a "daily Scrum meeting" does not matter)
Monitoring what remains to be done, who's doing what, and what's been done on a board (whether you decide to call that a "Scrum Task Board" does not matter)
Planning work in short iterations (whether you decide to call that a "sprint" does not matter)
Automating the build process
#2: Give your boss what he wants.
Your boss might ask you for things you believe to be useless, inadequate, or redundant as per your experience as a software development professional and your understanding of Agile development.
But he is your boss. So at first, I would recommend you just give him those things!
He believes a project is not a project without a Gantt chart?
Give him a Gantt Chart.
He believes a project is not a project without a Beta testing phase?
Give him a Beta testing phase.
He wants man-days?
Give him man-days.
Only you and your team will know that:
You have better tools than the Gantt chart for planning your work.
You care about quality throughout the whole project, not only at the end.
You measure effort in a different way.
#3: Be patient.
The good news, if you're trying to use Scrum and implement Agile development practices, is that basically . . . it works!
It's good news because, as you put those new practices in place, you'll see some results. All you have to do is make sure the rest of your colleagues also see them.
Show the product to everyone at the end of each iteration.
Show your boss some quality metrics.
It could take one or two years to change your boss's opinion from reluctant to skeptical. And another one or two years to make him a supporter. So be patient.
#4: Run away.
My fourth and final recommendation only applies if you've tried the first three and still aren't happy with how many Scrum and Agile development practices you are allowed to put in place.
In this case, I strongly recommend you just go and find yourself a better boss and a better place to work.
There's a lot for us software development professionals to learn out there, so let's not waste our time in companies that do not deserve our dedication.