I have designed a label format to print barcodes on Avery labels, but only the numeric portion of the Item Lookup Code prints on the label.

Code 3 of 9 does not support lower case characters. Try setting your barcode type to 128B or capitalize all characters in the Item Lookup Code.

For information on basic barcode formats see: http://www.barcodingfonts.com

We suggest 128A for mixed alpha-numeric Item Lookup Codes as long as letters are capitalized.
If you use our AutoGen add-in for RMS, the barcode type such as 128A can be assigned by default for all new item adds.