[TYPO3-commerce] How get a dropdown select in billing?

[Bert Hiddink]

Hello!

I tried the following to get a dropdown for the field gender in the 
billing-part:

plugin.tx_commerce_pi3 {
    billing.sourceFields {
	  gender {
		  type = select
		  values {
			0=man
			1=vrouw
		  }
		  default = man
		  mandatory = 1
		}
	}	
}	


This does not work but what  is wrong here? Any ideas?

Thanks in advance!

Bert