Concatenate Variables for Single Title-block Attribute??

I have a hard time explaining this. From .wdt file:

;; Attributes on title block are "mapped" to WD project data lines

;; and several CONFIG values. The form of each mapping line below

;; is either = LINEx

;; where "x" = project data line number (LINE1 thru LINExx)

;; or = xx where "xx" can be any of these:

;; = SHEET for WD CONFIG's sheet value (the %S value)

;; = SHEETMAX for count of drawings in the active project (ex: the "N"

;; value in title block "SHEET x of N")

I have a single titleblock attribute that I want to read "SHEET X of Y" where X is the individual sheet number and Y is the total number of sheets. I can't figure out how to use both the "SHEET" variable and the "SHEETMAX" variable for one attribute. Here's what I tried in the .wdt file.

I do not want to use two separate titleblock attributes for this.

TITLE 4 = "SHEET " SHEET " OF " SHEETMAX

AutoCAD Electrical 2012

Windows 7

Below is a link to ACADE discussion group which has a lisp routine TB_CONCATENATE. (All credit to the work of Nate Holt)

Copy and Load

Also below is a sample of how I use it to produce drawing numbers from the drawing properties dialog box and building sheet of sheetmax

The routine is an invaluable tool in my department

http://forums.autodesk.com/t5/AutoCAD-Electrical/How-to-combine-multiple-lines-of-proj-desc-text-and-write-out-to/td-p/.UNEHyzNuKKc

TITLE1 = DWGDESC

TITLE2 = DWGDESC2

TITLE3 = DWGDESC3

FILENO. = FILENAME

PRODUCTID = (tb_concatenate (list "IEC_I""-""IEC_L"))

DRAWINGNO = (tb_concatenate (list "IEC_P""-""IEC_L""-""DWGSUB""-ME""SHEET"))

SHTCOUNT = (tb_concatenate (list "SHEET"" OF "))

SHEETMAX = SHEETMAX

FILENO. = FILENAME

STATUS = LINE1