You really need to understand the ASCII format first. Look at Ppcb_ASCII.pdf.
You need to change all of the following layers:
121 to 21
126 to 26
128 to 28
130 to 30
And then import the decal back into a library. Hint, don't to this in Word and then save it in ASCII (txt) format; something gets corrupted. I did it in Notepad and had better results:
*PADS-LIBRARY-PCB-DECALS-V9*
DBF_277P_9P M 93.6244 37.3634 2 2 6 2 11 4 1
TIMESTAMP 2012.10.12.04.56.39
"HEIGHT"
"PART NAME"
-5.4864 -13.2334 0 0 2.54 0.254 1 0 34 "Regular <PADS Stroke Font>"
REF-DES
-5.4864 -13.2334 0 0 2.54 0.254 1 32 35 "Regular <PADS Stroke Font>"
PART-TYPE
OPEN 4 0.1524 26 -1
-13.8176 -13.2334
-13.8176 -19.5326
2.8448 -19.5326
2.8448 -13.2334
OPEN 2 0.1524 26 -1
-21.1836 -10.6934
10.2108 -10.6934
CLOSED 5 0.1524 26 -1
-21.1836 -13.2334
-21.1836 1.8034
10.2108 1.8034
10.2108 -13.2334
-21.1836 -13.2334
OPEN 2 0.1524 26 -1
-21.1836 -13.2334
10.2108 -13.2334
OPEN 2 0.1524 26 -1
-13.8176 -10.6934
-13.8176 1.8034
OPEN 2 0.1524 26 -1
2.8448 -10.6934
2.8448 1.8034
-12.2936 -18.5166 0 30 1.7018 0.0254 0 0 0 0 "Regular <PADS Stroke Font>"
Female
-4.318 -18.5166 0 30 1.7018 0.0254 0 0 0 0 "Regular <PADS Stroke Font>"
$ 544
T0 0 0 0 1
T-2.77 0 -2.77 0 2
T-5.54 0 -5.54 0 3
T-8.31 0 -8.31 0 4
T-11.08 0 -11.08 0 5
T-9.6012 -2.8956 -9.6012 -2.8956 6
T-6.858 -2.8956 -6.858 -2.8956 7
T-4.1148 -2.8956 -4.1148 -2.8956 8
T-1.3716 -2.8956 -1.3716 -2.8956 9
T-18.1864 -1.4478 -18.1864 -1.4478 10
T7.2136 -1.4478 7.2136 -1.4478 11
PAD 0 5 P 0.9398
-2 1.778 R
-1 1.778 R
0 1.778 R
21 1.778 R
28 1.778 R
PAD 1 5 P 0.9398
-2 1.778 S 0
-1 1.778 S 0
0 1.778 S 0
21 1.778 S 0
28 1.778 S 0
PAD 10 5 P 3.1
-2 4.5 R
-1 4.5 R
0 4.5 R
21 4.5 R
28 4.5 R
PAD 11 5 P 3.1
-2 4.5 R
-1 4.5 R
0 4.5 R
21 4.5 R
28 4.5 R
*END*
Note that you have to do this manually and very carefully, otherwise you might change a '121' that is not a layer definition and then you've corrupted the decal.