In general, I agree there SHOULD be no issue however:
I had an issue and did some research and it was recommended to replace my SATA2 cable with an official SATA3 one. A LOT of people say it makes no difference but since my SATA2 cable worked fine with other drives, and using an official SATA3 cable solved my issue I can't agree with that.
Having said that, many people don't have any issues with SATA2 cables on SATA3 hard drives. So go ahead and use it, then run a drive diagnostic to see if any errors occur.
These article for example, found no problems:http://www.pugetsystems.com/labs/articles/SATA-cables-Is-there-a-difference-97/http://www.maximumpc.com/article/features/your_sata_cable_slowing_down_your_data_transfers_max_pc_investigates
My ONLY explanation for the difference is a small percentage of cables were manufactured defectively and worked fine at lower speeds.