Creating iso both bootable and Live

Hi, guys!

I'm interested in creating iso with both items in isolinux.cfg
* Try this media (Live)
* Install OS (just bootable)

Currently I creating bootable CentOS-like .iso with lorax and have some experience with it. 
As I see, I can use livemedia-creator to create livecd .iso.

How can I combine two methods into one iso? As I remember, Fedora had this feature some time ago (or I miss something).
Should I do some magic to manually merge them? May be some one have such experience and can point me right direction?

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Regards,
Vit Ry.