Question about PHP logo usage

Dear PHP representatives, (webmaster@php.net was the only contact info I found in www.php.net but, in case this mail must be redirected to a different recipient, please forward it ot let me know. Thanks). I'm private consultant in software engineering working in north Spain. I'm a strong defender and like to promote free software in general an LAMP solutions in particular. I'm deeply working in getting experienced with Apache's http server, MySQL db and PHP developement tools, in order to help my customers to either migrate from other solutions or to create new functionalities for their organizations. I'm in the process of desinging some graphical material for my business cards, envelopes, letters, website... A part form my own logo, nothing to do with PHP logo, I plan to use, in the background, small grey images as icons representing the products I intend to give support to. This mail is to kindly ask you for permission for using PHP's logo in such terms. I understand this is good for both promoting PHP and for puting through my message of service fast and clear in my relationship with customers around my area. I would understand any answer, but in case you accept, please let me know which variant of the many variants the PHP logo has I can use. Thank you so much, Juan A. Budia