Shintrue,
Good news! I’ve finally been able to implement a solution that serves your purpose.
You can now override the buttons and URL given to them with the template tag and shortcode.
In your case, this is how you can add your follow button:
<?php wpsocialite_markup(array('button_override'=>'twitter-follow')); ?>
[wpsocialite size="small" button_override="twitter-follow"]
Be sure to select the “twitter follow” option in WPSocialites settings page, then add your twitter username.
This is coming in the next release, today, so be sure to update when you see it come through.
I’m marking this resolved, but be sure to check back if you have any issues.