Hi,
I have not worked with the plugin, but off the top of my head if you have the path of the file you could use the File Transfer API and pass that path as a download, since downloaded images are saved into the camera roll this should basically copy it over.
Another choice is to contact the developer of the plugin as see if they have plans or a an easier way. I have noticed some third party plugins have features built in that are not documented.
Thanks,