Using model attribute as :filename when using paperclip gem

I'm getting an error when attempting to change the :filename of my paperclip attachment to equal an attribute on the class I'm attaching the paperclip file to.

When I use "#{self.company_name}" it errors out. Apparently in this scope, "self" is not Company. When I wrote this line I assumed that self is the instance of Company that I'm uploading this attachment to. Any idea how I can fix this? The Paperclip docs say to use ":filename" but I'd like to use the value of Company.company_name instead.

class Company < ActiveRecord::Base
  include AliasAttrs

  has_attached_file :company_logo, {

      :storage => :ftp,

      :path => "/logos/#{self.company_name}",

      :url => FTP_CONFIG[:access_host]+"logos/:filename",

      :ftp_servers => [
        {
          :host     => FTP_CONFIG[:host],
          :user     => FTP_CONFIG[:user],
          :password => FTP_CONFIG[:pass],
          :port     => 21 # optional, 21 by default
        }
      ]
  }
end