(2X4GB) Ram Upgrade problem - OptiPlex 780 DT

I have ordered and bought two Kingston ram modules 2x4Gb in order to to upgrade my Dell780 DT.

The Ram Type is KVR13N9S8K2/8 (8GB PC3-10600 CL9 240pin kit).

http://www.kingston.com/datasheets/KVR13N9S8K2_8.pdf

According to Dell's document http://i.dell.com/sites/content/business/solutions/engineering-docs/en/Documents/optiplex-780-tech-guide.pdf (Page9) this memory kit should work on my system (after upgrading BIOS to A15 also) but unfortunately DID NOT.

I have the lights 1 & 3  litted with a buzzing sound without booting.

Reading a numerous posts i saw that there are many posts concerning memory incompatibility of Dell780.

Can you find me any solution about my problem?

Why at Dell's guidebook page 9 you report that this machine can operate with 1333Mhz memory types?

I contacted  the memory seller and can't accept any return of the memories i purchased, because they are unsealed.

Do you have any plans to update the  BIOS to a compatible memory upgrade version if this can be  a solution, otherwise to look for selling my memory kit as used and buy another.

Thanks in advance.