partial mantel test

I would like to know how to run  a partial mantel test controlling for spatial 
autocorrelation and correlation with other environmental variables. It seems that 
with function included in vegan for partial mantel test I can only test for the 
relationship between two variables controlling for the effect of a third one.
Thanks a lot
Alexandra
---
Lic. Alexandra Sapoznikow
Centro Nacional Patagonico - CENPAT - CONICET
Bvd. Brown S/N
Puerto Madryn, Chubut, Argentina
Tel: 54-2965/451024/450401/451301/451375
Fax: 54-2965/45154
E-mail: alexa at cenpat.edu.ar