Need help repackaging component of Multiple Upstream Tarball package

Hi,

I'm trying to make Termite terminal emulator available for Debian. The Termite project consists of 3 separate source code repositories so I decided to pack it as Multiple Upstream Tarball package. One of these repositories is autotools-based and contains "autogen.sh". As far as I understand autotools workflow, the source tarball for this component should contain not pristine content of the git repository but generated output of autogen.sh. And this seems like a perfect job for repack functionality of uscan. Here is the content of my current debian/watch file:

version=4
opts="filenamemangle=s/(?:.*)?v([0-9]+)\.tar\.gz/termite-$1.tar.gz/" \
https://github.com/thestinger/termite/releases (?:.*)?v([0-9]+)\.tar\.gz
opts="filenamemangle=s/(?:.*)?(\d+\.\d+\.\d+\.a)\.tar\.gz/vte-ng-$1.tar.gz/,repack,component=vte" \
https://github.com/thestinger/vte-ng/releases (?:.*)?(\d+\.\d+\.\d+\.a)\.tar\.gz ignore debian/repack-vte.bash
opts="mode=git,component=util" https://github.com/thestinger/util HEAD ignore

According to the uscan documentation and this guide (https://wiki.debian.org/BenFinney/software/repack), "debian/repack-vte.bash" should be called with 2 arguments: "upstream version" and "downloaded file" name. However my script is called only with single "--upstream-version" and moreover the value is wrong - it's not the version of the component but the version of main tarball. As a result there is no clean way to obtain downloaded file name to repack it and I'm generally not sure that I'm on the right track with this approach.

Is this a bug that repack script for a component is called with the wrong version and without filename?

Am I using the right tool for the job? Is this approach sane?

Any help would be greatly appreciated. Thanks in advance!