[TYPO3] renderObj and custom script

[Bartosz Aninowski]

Hi
Can you point me to some how-to?
I want to use renderObj with my custom php script fg:

includeLibs.select_records = fileadmin/user_some.inc
my.renderObj = USER
my.renderObj.userFunc = user_some->select_records
my.renderObj {
10 = TEXT
10.field.someFiled1

20 = TEXT
20.field.someFiled2
}

What exaclly my functions select_records should return and if it possible at 
all?