Alpha conversion in Transfer rules

Hello,

A 'Z' field i.e. a Char. has a ALPHA conversion routine. This infoobject is used in an ODS. But when I load data from R/3, it errors saying 'InfoObject /BIC/ZREFNMBR does not contain apha-confirming value xxxxxxx.

How do i get rid of this error:

a) Do i remove the ALPHA conversion routine--> I can but this infoobject is used in many other cubes.

b) Make changes to the transfer structure..

or c) Please suggest.

Regards,

KS