I have same problem with Acceleration button missing, using Intel RST version 12.5.0.1066.
RAID enabled in BOIS
Corsair Force GS SSD Intel SATA III connector 128GB
WD WD1002FAEX HDD Intel SATA II connector, 1TB, Windows 7 install
Asus P8 Z77-V LE PLUS MB
I have an additional WD disk 2TB used for data only. RST only gives me option to create a RAID volume but no option to Accelerate.
