[R] gamma regression (Zelig package)

Hey, I want to estimate to regressions. First I want to estimate simple OLS. Since my dependent variable looks like a gamma distribution I want to estimate a gamme regression with the zelig package. But, I have some problems with the interpretation of the estimated coefficient. In the OLS the

[R] Nonlinear restrictions in systemfit

Hey, I want to implement a structural model with the package systemfit with some linear and nonlinear constraints. How to implement linear restrictions is clear. Does anybody know how to set up nonlinear restrictions in the systemfit packages. For example: beta1 = beta2-(beta4/beta6) I look