Kathy
I think it should be possible to solder on nickel since as you solder on nickel- gold, what you solder on is actually the nickel, gold prevents the nickel from oxidising. 
What you have to do is to remove the oxide layer that inhibits any alloying of nickel and tin. 

Possies:
- Mechanical 
- Etching

The problem is, that the nickel reoxitises pretty fast. I couldn't give any number though.
 
So the way might be: 
- Etch, hurry up and solder ( I think hydrochloric acid might do the trick, however you could ask the people that produce NiAu plated PCB's)
- Brush, hurry up and solder

Best regards

Guenter


EMPA
Swiss Federal Institute for Materials Testing and Research
Centre for Reliability
Guenter Grossmann,  Senior Engineer

8600 Duebendorf
Switzerland

Phone: xx41 1 823 4279
Fax :     xx41 1823 4054
mail:     [log in to unmask]

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