gistfile1.rb

# app/decorators/mailers/refinery/inquiries/inquiry_mailer_decorator.rb

Refinery::Inquiries::InquiryMailer.class_eval do
  def confirmation(inquiry, request)
    @inquiry = inquiry
    mail :subject   => Refinery::Inquiries::Setting.confirmation_subject(Globalize.locale),
         :to        => inquiry.email,
         :from      => "my_custom_from_name@something.com",
         :reply_to  => Refinery::Inquiries::Setting.notification_recipients.split(',').first
  end

  def notification(inquiry, request)
    @inquiry = inquiry
    mail :subject => Refinery::Inquiries::Setting.notification_subject,
         :to      => Refinery::Inquiries::Setting.notification_recipients,
         :from    => "my_custom_from_name@something.com"
  end
end

Thank you!