I can't tell if you are having trouble finding the new image, or actually connecting to the cRIO.
If you cannot find the V27 image then you may need to download the latest LabView update. The new image is included in the update and will be selectable from the imaging tool once installed. Update is
here.
If you are having connectivity issues then I would recommended going through basic network diagnostics. Check to make sure all static IPs are set correctly.