Well, the code looks like its pretty simple. Now to figure out what all the bits mean.
The 'String' is Base64 encoded.

Using some of Nemi's templates, and decoding them gives you (in hexadecimal)..

Elementalist / Ranger; no attributes; no skills
'AmAAAAAAAAAAAAAA' -> 02 60 00 00 00 00 00 00 00 00 00 00
Elementalist / Ranger; 1 point in Air Magic; no skills
'AmEAGAAAAAAAAAAAAA' -> 02 61 00 18 00 00 00 00 00 00 00 00
Elementalist / Ranger; 2 points in Air Magic; no skills
'AmEAKAAAAAAAAAAAAA' -> 02 61 00 28 00 00 00 00 00 00 00 00

You can see the air magic attribute increase.

Elementalist / Ranger; no attributes; rez sig in slot #1
'AmAAIAAAAAAAAAAA' -> 02 60 00 20 00 00 00 00 00 00 00 00
Elementalist / Ranger; no attributes; rez sig in slot #2
'AmAAAgAAAAAAAAAA' -> 02 60 00 02 00 00 00 00 00 00 00 00

You can see the rez sig move over a slot here...

Just as a guess, the first '0' is a template version number
The '2' is Elementalist.
The '6' is Ranger.

Next 3 digits are a description of what follows in the rest.
Shouldn't be too hard to figure out from there given a few templates (and knowing what they are supposed to be)