creating a series from alphanumeric data?

I've tried several things to accomplish this with no luck, but I'm sure it's not too tough to do:

On my worksheet, I am entering columns of cells with alphanumeric data. The data are actually thousands of reference numbers that need to go in chronological order, with only the numerals changing (e.g., ABC0001DEF, ABC0002DEF, ABC0003DEF..., with "ABC" and "DEF" always the same).

I can create a series just fine if I leave off the "DEF" part of the reference numbers (by selecting the first couple cells in the series and using the fill handle), but I can't get the same results with the numerals "nested" within the reference numbers (i.e., ABC####DEF).

It sure would save me a lot of typing to be able to create a series to fill in all my reference numbers! Any ideas?