Question about how to use external function with returns

Hi, dear Professor,
I encountered a problem in estimation with a external function.
I have a external function as :
#x = fsolve(@(x) ratiosolve(x,Z_gOZ_m,A_gOA_m,alpha,ita_n,epsilon_y,gamma,iota),[0.8;0.8;1.5]);
in the estimation, where x is a three-variables vector.
but it seems dynare can not do with the symbol"@", it goes wrong as below:
"ERROR: misallobey.mod: line 131, col 13: character unrecognized by lexer"
So what should I do if I want to use an external function with a vector-form return?

Use a _steady_state-file to call the solver there.

THANKS LOT , Dear Prof. Pfeifer!