Auto Generate Customer ID

Question

Hi,
I m creating one small application in asp.net for my practice.
Let take one example, customer registering information in the website like firstname, lastname,dob,etc. after metion the personal details customer need to generate his/her ID by clicking on button.
Customer id format 2aplha & 4numeric, system should automatically want to generate.
example:
Praveen Bahubali is my name, for this customer id should come
PB0886 (0886 is my dob mm/yy)

Can any one help this logic.

Thanks
Praveen Bahubali