Making a multisession bootable cd/dvd

[devaj]

I am trying to make a boot cd from an iso image.After burning the image I would still be having 200 mb of free space.Is it possible to add data after burning the iso image aka multisessioning it.I tried nero but it doesn't offer me the track at once option,only disc at once is available,while ultra iso offers me the track at once option.Any help would be greatly appreciated.
Thank you

 

[devaj]

I would really appreciate if any of the great minds here could shed some light on this.