Hi, I remember I once created a DVD that was playable in a regular DVD player, but I made one of the "chapters" a data section, that when the DVD was loaded on a computer would have files to access.

I know this is not uncommon with DVDs, even those that you purchase.

Can the same be done with Blu-Ray? The one software (Roxio I think) I got to tinker with didn't seem to have an option to create a data chapter.

Is it as simple as also just creating your own directory on the Blu-Ray and placing your files there? I have never burned a blu-ray so perhaps this is obvious once you get started?

Sony puts PS3 themes on theirs so I would I say yes.

so next question is how? I guess I would create the files in a directory 1st, then insert the disc for burning... and it will use the space it has left?

Just make a new folder on the root of the disc, or place the files on the root of the disc, and include what you want. So long as the folders necessary for BDMV operation are in there (BDMV, CERTIFICATE, etc), the disc should play.