In version 7.9 the field metadata array changed a bit. This data was converted during an upgrade but on a fresh install some packages are not working properly because they never went through the convert process.
I found the code that does the conversion upgrade/scripts/post/1_UpgradeRelationshipFields.php
I was able to replicate the functionality in the post_install but there are some functions (glob(), and write_array_to_file()) that would be banned by the installer for On-Demand. I tried calling the class directly but there is a required ($upgrader) parameter that must be passed when initiating the class and I'm not sure what that would be.
Any suggestions would be greatly appreciated.