I am using Word 2007.

I put a lot of numbered texts in my documents like the following:

(2) a. I painted last week.
b. I applied last week.

(3) a. John brought the sandwiches and Ann ate.
b. John picked up the glass of beer and drank.
c. We needed a lot of pastries for the party.

I insert the numbers by Word numbering menu but insert the alphabets manually using SHIFT-ENTER to get new lines. When I insert a cross reference to them, the numbers appear the same, that is, in parenthesis. So If I want to refer to (2)a:

i) I insert (2) with cross-reference menu
ii) manually add "a" and get (2)a
iii) put them in parentheses and get ((2)a)

But this is bad. Books and journals want (2a), not ((2)a). To get (2a), I need to insert 2 instead of (2) with cross-reference, but is this possible with Word 2007 or any other versions? (I cannot change the text numbering format to 2.)

A better solution might be to enter the alphabets also with the numbering menu instead of manually. But I am not sure if this is possible. I would greatly appreciate your help.