I have the same board with the exact same problem. Same model of MSI card. I have been unable to get it to post in the DX58SO. I have however been able to get the card to work in SLI mode with another mfg card, a PNY. So there is either something wrong with the motherboard's support for this card, or with MSI. According to the MSI forums, it is an issue with the DX58SO as it is a known problem board.
Why is it I can get the card to work in SLI as a slave, but I can not get the card to work alone. Rather frustrated that other cards do work and this one brand will not. Do we need a bios update to fix this?