Link to app outside PortableApps directory or link to app data instead

(If there is a better forum to post suggestions for developers, please let me know.)

Instead of adding an app to the PortableApps directory, I'd like to place it somewhere else, and have a link at the PortableApps directory pointing to that other place.

There are currently two limitations:

1. Portable applications must be located inside the PortableApps directory to be automatically added to the PortableApps start menu. (As far as I understand.)

2. Some portable applications don't allow storing data outside their installation directory. This may not be true for all. I only tested Calibre (ebook management) and Mozilla Thunderbird (email and address book client).

Two examples where removing at least one of those limitations would be useful:

1. I share a Calibre Library of ebooks with my family using a Dropbox folder that I keep in a USB drive.
PortableApps is installed in the same or different USB drive.
The portable version of Calibre does not support a library in an arbitrary location. It has to be under its installation directory.
Therefore, to share the library, the software has to be installed in the dropbox folder. But then, it doesn't show up on the PortableApps start menu.

2. I use Thunderbird just for the address book. I share it with my wife, by placing the Thunderbird "profile" folder in dropbox.
As with Calibre, the portable version of Thunderbird does not support having the profile outside the installation directory.
Therefore, to share the profile, the software has to be installed in the dropbox folder. But then, it doesn't show up on the PortableApps start menu.

Thanks to anyone that took the time to read this!

- Edgardo.