Append limits in Dataflows

Hi,

I need to deliver a dataflow that is the merge of two csv files in SharePoint plus some transformation.

I need to have visible, in the dataflow list, just one table that is the merge of the two csv.

I found that:

 - I can create a table in the dataflow from one csv file but I cannot append another csv, I can just append a query selecting a table from the same dataflow, nothing more, there are no other options in the "append" .

- if I create, in the dataflow, two tables, factT1 and factT2, one for each csv that I have to merge, and then create a new table that is the append of the two, I cannot save the dataflow since it gives me an error:

Linked tables can't be modified. Please undo any changes made to the following linked tables and try again: factT1 (2)

- it only works if I create a table in the dataflow, factT1, from the first csv and then create the other table, factT2, from the seconds csv but at this point in the query of factT2 I select append the factT1.

The result is that I have both factT1, merged in factT2, and factT2 visible in the dataflow list.

Thanks in advance for any support.