You actually can work with Snarlys subdivider.
But there are some things to be aware of:
The subdivider creates a new (subdivided) figure in Poser's hierarchy tree, so you have to hide the original figure before going to Octane.
Once subdivided, you can't no longer pose or morph the subdivided mesh. If you want to make any changes, you have to delete the subd'd figure, go back to the original figure, change it, and then subdivide again.
If you have special shaders for your figure, it makes sense to put your original figure into the plugin first, apply your shaders there and save them back to the Poser materials. When you subdivide the figure later, all the Octane materials will be transfered to the new figure and you don't have to reassign them.
Win8.1/64Bit | i7-950 | 12GB | GTX Titan 6GB | NVidia Driver 431.36 | Octane 4.05 | DAZ Studio 4.12 - Plugin 4.04