Textbox are not promoted to mult-line textbox on sharepoint library

[kangaJack]

Hi

I am using an infopath form to populate a sharepoint forms library.
The problem is textboxes, despite being configured as mult-lines,
appear in the sharepoint document library as single-line datatype. I
understood they should have been promoted to multi-line data type.
Does anyone know if this is bug and/or how I can can convert infopath
text boxes into sharepoint multiline text boxes.

Cheers
Laurie