Citroen C2 2004 HDi ECM Replacement

Hi professionals.
I have in the shop a Citroen C2 HDi 2004 model with SID804 ECU and i want to replace the engine ECU.
I also have the original car pin code.
I have ordered a used Virgin ECU with same numbers as the original.
The problem is that when i am going to match the ECU, Lexia asks for confidential code but when i try to enter the code Lexia don't accept any letter in the code only numbers.
My code contains letters and numbers so i am stuck.
I have already tried once to match it with wrong code so now Lexia says i have only 2 tries left.

Does anyone experienced something like this before?
Thanks.