Ibn Humam over Istishfa'a

Ibn al-Humam al-Hanafi says in "Fath al-Qadeer" (2/337) on visiting the prophet's grave:
3- الإمام كمال الدين بن الهمام الحنفي رضى الله عنه ( ت:861هـ ) فتح القدير، ج2، ص332، كتاب الحج، باب زيارة النبي صلى الله عليه وسلم:
ويسأل الله حاجته متوسلا إلى الله بحضرة نبيه ثم قال يسأل النبي صلى الله عليه وسلم الشفاعة فيقول يا رسول الله أسألك الشفاعة يا رسول الله أتوسل بك إلى الله.
"Then let him ask Allah for his need, using Allah's Prophet as his means to Allah; (then he said): Let him ask the Prophet for his intercession and say: "O Messenger of Allah, I am asking for your intercession; O Messenger of Allah, I am using you as my means to Allah".