Another way you can get data pre-entered into a program file is to create the data file in Logix500 and then export the program as a .SLC library file.
You can then open the .SLC library file with a text editor or word processor, find the data file definition, and then cut/paste the numbers in. Save as a text file with a .SLC extension and then open the .SLC file in RSLoigx500. Then save it as a .RSS file.
Look at the attached example file. The file is a .SLC library file (text) export of a blank ML1400 program. If you open this file you'll see a section marked with the label Data N:10:0, followed by values 0 to 255. I opened an excel spreadsheet and filled 10 columns by 26 rows with sequential numbers. Then selected the data and copied it. Then with the .SLC file open in notepad I pasted it right under the N10:0 label replacing the 256 zeros that was there. I saved the file as a text file with the .SLC extension and opened it in Logix500. Then opened the N10 file and all of the values were there. I've attached it as a .txt file so if you want to try it out change the extension to .slc.
You will mainly find this useful if you already have a long list of values to enter from a spreadsheet or other document from which you can cut/paste.
For a single data file one by one entry doesn't take all that long once you sit down and just get to it.
You may want to take a minute to open the file properties and click help, then follow the link to the create file dialog help and read up on protecting files as static, and memory module protection, etc.