Maintaining Email Title In Nace for Invoice

Hi ,

I have a requirement to maintain Email title for my outpu type.

I use the print Program : SD_INVOICE_PRINT01.

In Nace for my output type I have configured the Program : SAPMV60A and Form Routine as TEXT_SYMBOL_REPLACE.

In the Email Titile I maintain Invoice &VBDKR-VBELN& /  &VBDKR-BSTNK&.

But In my mail I donot get any email title.

This requirement is a high prio one as I need to configure email title for amny output types.

If any one had done this sort of development indly let me  know.

Thanks.