Take a look at get_v_postl_cod1 method of ZL_ICCMP_BP_BUPAADDRSTD_CN00 class, this is the getter method for post codes in account overview. Inside you'll find something like this:
country_id = get_s_struct( attribute_path = 'STRUCT.COUNTRY'
component = 'COUNTRY'
iterator = iterator ).
...
...
...
SELECT * FROM adrpstcode INTO TABLE lt_adrpost_code
WHERE country = country_id.
You can fetch region value in the same way as country value and modify select query to include your region data. These tables should provide with all required data: ADRPSTCODE, ADRCITY, ADRCITYT, ADRPCDCITY, ADRPOBOX, ADRCITYPRT, ADRSTREET, ADRSTREETT, and ADRSTRPCD.