hp 50 keys in program

[Donseba]

Hi brothers.

My question is a liitle particular.

I know that all keys in hp 50g can be represented by row, column coordinate.

For example key "ENTER" is (10,6), but

What command must be used, for replace ENTER by xxx (10,6) in a program?

example:
<< "hola amigo" ENTER>>

replace for:

<<"hola amigo" xxx(10,6)>>

Thanks for your help.