Prepopulate the PayPal Form Variables

Only some of the Buy Now fields are pre-populated.

I need the correct variable names.

Here is my form code:

<form action="https://www.paypal.com/cgi-bin/webscr" method="post">

<input type="hidden" name="first_name" value="David"/> OK
<input type="hidden" name="last_name" value="Martin"/> OK
<input type="hidden" name="address_street" value="7005 Southwind Drive"/>

<input type="hidden" name="credit_card_number" value="abc"/>
<input type="hidden" name="city" value="Biloxi"/> OK
<input type="hidden" name="state" value="MS"/> OK
<input type="hidden" name="zip" value="39532"/> OK
<input type="hidden" name="telephone" value="228-396-5708"/>
<input type="hidden" name="mm" value="01"/>
<input type="hidden" name="yy" value="13"/>
<input type="hidden" name="email" value="dovberman@cableone.net"/>  OK
<input type="hidden" name="no_email" value="1"/>
   
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
<input type="hidden" name="cmd" value="_s-xclick"/>
<input type="hidden" name="hosted_button_id" value="2GEF2YNF55VLJ"/>

<input type="image" src="https://www.paypal.com/en_US/i/btn/btn_buynowCC_LG.gif"  
    name="submit" alt="PayPal - The safer, easier way to pay online!"/>
<img alt="" border="0" src="https://www.paypal.com/en_US/i/scr/pixel.gif" width="1" height="1"/>

</form>


The input fields marked OK are prepopulating.
I have determined that I need the correct names for them.

For instance <input type="hidden" name="address_street" value="7005 Southwind Drive"/>
does not prepopulate because "address_street" is not the correct variable name.

Where can I find the correct variable names?

Thanks,