How do I map a "Formula Field" or the "First Name"/"Last Name" when converting a lead to an account?

How do I map a "Formula Field" or the "First Name"/"Last Name" when converting a lead to an account?

My ORIGINAL PROBLEM was:

(1) In the "Leads Detail Page", i wanted to see the "First Name" and "Last Name" separately >> I didn't want them to be displayed together as "Lead Name".
(2) In the "Accounts Detail Page", i also wanted to see the "First Name" and "Last Name" of the original lead from which they are converted.

My SOLUTION was:

For Problem (1):

I created 2 formula fields named "Given Name" and "Surname". I used the "Upper" function and the "First Name" and "Last Name" fields respectively.

For Problem (2):
Since the data in the "First Name" and "Last Name" of the leads module is carried over as a new contact, instead of going over to the new account, I created 2 new text fields "First Name" and "Last Name".

Now, a NEW PROBLEM i have is that, I want to map either the new "Formula Field"s i made in the leads module OR the standard "First Name" and "Last Name" fields in the leads module when they are converted to account.