How to generate iron router link with parameter from within helper

I want to generate the html code for a specific iron router link within a template helper.

I’ve tried various options:

var link = Router.routes['find_contact_persons_page'].url({_companyId: this._id});

This returns null.

var link = Router.routes['find_contact_persons_page'].handler.path;

This returns:

Which is correct but how do I then in a smart way generate the full link with the correct parameter inserted?
It cannot be true that I have to do string replace, etc. to create it.
I have been unable to find any docs on how to do this.

This is the way to do it:

var link = Router.routes['find_contact_persons_page'].path({companyId:this._id});
return new Spacebars.SafeString("<a href=\"" + link + "\"> Click Here</a>");