Chen, according to the the description you provided, this field is exactly what I need. I see no problem using it, it's just add a lookup field in the form. The one million question is, why this is not apperarig in the HTMPL files (cmdb_detail.htmpl and related)? Well, I don't think I need to open a support case, since it's not a error or a malfunction. I'm asking it just out of curiosity, no need to worry.
Well, maybe this question will remain without a response for a long time...
Thanks,
Diogo