There are (at least) two ways you can set where knife bootstrap finds Chef packages.
knife bootstrap --bootstrap-install-command [curl path to your package repository | sudo bash]
knife bootstrap --bootstrap-url [URL to your own custom install script which happens to use your package repository]
What follows is information to help you decide which of these you want to try.
The source code that controls this is in these two files:
bootstrap.rb evaluates chef-full.erb to create the bootstrap install script. Option 1 overrides a block in chef-full.rb and replaces it with your own bash < curl command combo.
If you choose Option 1, we strongly recommend that you have the command in a script that you keep in source control and that you run that script. We suggest calling it something along the lines of [YOUR COMPANY NAME HERE]_bootstrap_node.sh. At it's most minimal it'd contain "knife bootstrap --bootstrap-install-command [YOUR CUSTOM bash < curl command]". To bootstrap your nodes, you'd call this script.
If you use Option 2 to specify your own template, you'd tell bootstrap.rb to skip processing the chef-full.erb and just use the bootstrap script you specify. In this case, we recommend you put your script in source control. The most important thing this script needs to do is the same bash < curl command you'd supply with Option 1. If you have more customization beyond the package location, you may find this option appealing.