Multivariate regression beta maps z-transformation?

Hi there,

I have used Conn to run a multivariate seed based analysis to look at the unique correlation of 1 seed, while correcting for two other seeds. As output in the first level analysis I get the BETA maps per subject and source. However, to continue to second level analysis, I have to z-transform these regression coefficients, right? The only way I can find to do so, is by dividing it by the standard deviation. However, where can I find these variance maps/SDs? Is there an option in conn toolbox to output these files? 

Thank you,

Margo