Parker window screen spring replacement

[finfish1]

Can anyone show/tell me how to modify the screen windows so I may use the plastic springs I purchased this last "spring", would like to use them, instead of replacing the rusty steel springs each year.
Thanks,

Reel Job

 

[big tuna]

Where do you even get the steel springs from? I replaced mine once and they came directly from Parker for free. I'd like to know where I could buy some for the future.