No Accelerate button/tab on Intel Rapid Storage window

Finally got the Accelerate button to appear! The issue appears to be that I had formatted the SSD when it needed to be Unallocated space:

Once I deleted the volume and re-started the Intel Rapid Storage Technology application the Accelerate button was present and I was able to use the SSD to accelerate the HD.

If setting up RAID in BIOS, emptying the SSD/cache disk and putting it offline still doesn't work, you should shrink the C: drive a bit. Worked for me!

I tried everything above, nothing worked.

In the end I downgraded the driver by the one provided by manufacturer [Dell] (v12 instead of v16) and it works now.