Automatically downloading of required packages

Hello everyone,

I maintain a library + toolset (called "Pawn"), for which I created an
autopackage. Some functions of the my software depends on the "libffi"
library which I did not write (and do not maintain). I made an autopackage
for it.

Next, I want that libffi to be downloaded and installed when some installs
my "Pawn" software (and libffi is not already present). Here is where it
fails.

I made a skeleton for libffi, and copied that to the directory where I found
the other autopackage skeletons. The skeleton has a link to the luau file
(which is on our company web site). The luau file has a link to the libffi
package. I put the root name of the skeleton the the specfile of Pawn.

When I install the Pawn package and libffi is already there, all is fine.
When libffi is not there, autopackage tells me that it is missing and that
the installation if Pawn failed.

I tried to follow the documentation, but I probably overlooked something.
Thanks in advance for any help,
Thiadmer Riemersma