Start a multisession with neroCMD

Hello to all the N.G.

I’m making some experience with NeroCMD. The string to burn a multisession disk work fine if the disk is not empty. If the disk is empty, I have to remove the --import parameter, to burn the disk. Is there a way to walk around?
Is there a way to detect if the disk has a session on it or not, without using the API?
The string is inside a shell called from an application, and I would like to automatize the process.