Django runserver in command with custom settings

I try to execute the runserver inside a command with custom settings. But the settings are not loaded:

from django.core.management.base import BaseCommand
from django.core.management import call_command
from django.core.management import setup_environ, ManagementUtility

import settings_api

setup_environ(settings_api)

class Command(BaseCommand):
    help = "Local API to retrieve realtime quotes"

    def handle(self, *args, **options):
        if not settings_api.DEBUG:
            call_command('runserver',  '127.0.0.1:8002')
        else:
            call_command('runserver',  '0.0.0.0:8002')

Output is:

Used API settings
Used API settings
Validating models...

0 errors found
Django version 1.4b1, using settings 'site.settings'
Development server is running at http://0.0.0.0:8002/
Quit the server with CONTROL-C.