Printing a Long text in SAP Script

Hello,

Is there any way that i can concatenate 2 or more fields and pass the value to another field and use that value in an INCLUDE statement to print a Long Text in the layout.

INCLUDE XXXXXXX OBJECT 'DOC_ITEM' LANGUAGE 'E' ID '0001' PARAGRAPH 'ZI'

In the above statement i have to pass this value '103740000000402006001' to get the text.

The above value is the combination of Company Code, Invoice Doc Number, Fiscal Year, Line Item Number.

i,e.. the combination of the following fields:

&REGUP-BUKRS&&REGUP-BELNR&&REGUP-GJAHR&&REGUP-BUZEI&

Thanks in advance.

Suresh