Filter not allowed characters - carriage return/line feed?

Hello community,

we're facing not allowed special characters in a unicode-BI 7.0 when extracting data via 0FI_GL_4. In the "freetext"-fields (e.g. reference key). Especially we face carriage return/line feed encoded as a square-symbol.

How could we filter this symbol out as we could not copy and paste it to a formula rule in the transformation.

Any ideas?

manuel