Hi Praveen,
Christian is correct about XSLT being the fastest method in a transaction. You could alternatively build an MII Document and map the columns, but it will not execute as fast. You are also correct that the DB has the same field names.
On the other hand, I would recommend getting used to the field names as defined in the incoming IDoc. I find little value in making the transformation when the data presentation does not generally show the field names and you could do the labels using MII language tools.
Is there another reason to you wish for this change this besides unfamiliarity with the field notations?
Regards, Mike
SAP Technology RIG