HI - I know this article is a little dated, but I am curious if you ever found a solution to your issues. We are having very similar issues, using exactly what you have. The IBM V7000 Storwize, VMware SRM version 5, and ESXi 5 Update1.
I know we've had to adjust some of the storageProvider settings, under Advanced Settings for both sites (protected and recovery) but that hasn't solved all of our issues. We still have failed tests, with random and similar errors.
If you can, will you update this discussion as to what you did to resolve your issues? Also, all of our LUNs are in consistency groups, which are in various Protection Groups, depending on the test I am performing.
Thank you!