Так описание этого параметра вроде толковое:
Code:
FU BAPI_MATERIAL_SAVEDATA MATERIALLONGTEXT
Description
You use this structure to transfer the long texts for the material.
For information on the meaning of the individual fields in the
structure, see the corresponding data element documentation for the
individual fields.
Note
Different long texts (basic data texts, purchase order texts, internal
comments, sales texts, material memos) can be created for a material.
This requires the fields APPLOBJECT, TEXT_NAME, TEXT_ID, and LANGU or
LANGU_ISO in table parameter MATERIALLONGTEXT to contain entries.
Depending on the content of field TEXT_ID, the field TEXT_NAME must have
the following structure:
The material number is transferred first. If it has fewer than 18
characters, the remaining characters must be filled with blanks. If it
is a material memo (LTXT), the plant key must also be transferred from
character 19 onwards; in the case of a sales text (0001), this must be
the sales organization and distribution channel. The combinations
allowed for the four different fields are indicated in the following
table:
APPLOBJECT TEXT_NAME TEXT_ID LANGU
MATERIAL Matl no. (18 char.) BEST, GRUN, or IVER Language
MDTXT Matl no. (18 char.) LTXT Language
Plant
MVKE Matl no. (18 char.) 0001 Language
Sales organization and
distribution channel
Что именно в заполнении не понятно?