Upload file from mobile app

Hi,

We are trying to upload a .XLS or .CSV file from a mobile app.
So far we are exporting the file content as XSTRING from mobile to a custom RFC that calls function SCMS_XSTRING_TO_BINARY to get the binary.

The issue is that the binary_tab doesn't came with binary content, it throws the same xstring data.
We guess it could be the structure type, I have read several post and use the following types without luck:

x255

x

any

solix

solix_tab

sdok_sdat
sdokcntbin

sdokcntascs

Any idea to solve this, or to upload a file from iOS device?

Regards,
Francisco Silva