domain mapping/Mutli-domains - use 2 domains as main domain

Hi,

My goal is to be able to use the main-domain-com and second-domain-com (with no redirection one to the other)

My issue is that after mapping the second domain I get my main-domain-com redirected to the second-domain-com

In "administration mapping" I selected "original domain"

In apache (httpd.conf) I added the path to the main-domain-com folder to the IP address,
but when I type the IP address it is redirecting to the second-domain-com

I'm also using Multi-Domains plugin.
I understand that the purpose of Domain Mapping plugin is to map a domain to a blog, I need that feature but also need to have 2 main domains as I have Multi-domains plugin enabled.

Any advice is appreciated.