Could you explain a little more about how you communicate between your PC and the Opto22 PCI-AC5?
My guess is that it probably has various drivers and that you could call into the the dlls and make the various calls necessary to operate the board by having LabVIEW call into it. You might also contact Opto22 and see if they would develop a LabVIEW driver that could better access the board. Finally, you could contact an Alliance member and see about them developing a driver for you.
Best of luck,