A way to build an ubuntu-based package with custom patches with recipe

Hello.

I want to automate applying custom homemade patch to ubuntu package (namely xkeyboard-config). I thought it can be achieved with packaging recipe like following:

> # bzr-builder format 0.3 deb-version {debupstream}-0~{revno:patch}
> ubuntu:quantal/xkeyboard-config
> merge patch lp:~develop7/xkeyboard-config/rube-layout

This approach failed: build bot didn't know how to handle "ubuntu:" bzr scheme

Next try with
> # bzr-builder format 0.3 deb-version {debupstream}-0~{revno:patch}
> lp:ubuntu/quantal/xkeyboard-config
> merge patch lp:~develop7/xkeyboard-config/rube-layout
failed too: https://launchpadlibrarian.net/131430922/buildlog.txt.gz

Even branch stacked on branch in ubuntu was failed to check out by bot as well — https://launchpadlibrarian.net/131436617/buildlog.txt.gz

Not mentioning that lp:ubuntu/quantal/xkeyboard-config contains version older than one in repositories.

So, are there ways how to make this possible without patching package locally and uploading it to PPA?

Thank you in advance.

P.S. Recipe that doesn't work resides in https://code.launchpad.net/~develop7/+recipe/xkeyboard-config-rube-daily