Assuming as your data source will be based on function module.
then you need to implement a logic to pull text data as well.
Take abap expert help and pull text as well.
on same time data source need to have a text field which can hold text values.
Another way:
You can maintain master data source/text based on your ecc table.
Thru text data source(custom) you load txt data into bw obejcts.