Frontmatter on proxy pages

First of all: Hi to all and thanks for the great middleman!

My question is, if there is a way to create Frontmatter for proxy pages when creating them.

To be more specific:
Right now I am working on a dynamic navigation forked off of middleman-navigation, which generates Childpages and everything as well.
Everything works so far, but I have a medium problem with proxy pages, as the frontmatter from the template is also used for the childpages.
Is there a way to eather set the frontmatter in config.rb, when generating the pages, or to grab some local variable in the template and store it to the frontmatter?

Another way would be to grab the local data for the proxy pages inside the navigation code, which would implement to make them accessible for other pages. Is that possible alternatively?

Best regards and I hope to be able to share my completet code soon.

I haven’t worked with proxy pages, but I know you can access frontmatter from the sitemap resources, and you may be able to add values using something like add_metadata.

Did you ever find a solution?