You'll want to create an instance of the SCLogin module and configure it how you want it to work. Then, set it in a position of "custom_sclogin". You can use whatever custom name you want for the position.
Then, in your article, use the following tag:
{loadposition custom_sclogin}
The reason to do that is so that you are loading the exact SCLogin instance configured how you want. If you just do {loadmodule mod_sclogin}, you'll be using the default settings of the SCLogin module and that may simply not work if it's not configured properly for your site.
Hope that helps,
Alex