Jose,
The error happening was: after compiling and executing a DSL, the DSL editor could not show any drawing. Instead, a xml apeared.
I don't know if it's related to GAX/GAT, but it seamed to me, because this problem happened just after instaling it.
I've just reintalled VS SDK and now everything is working well (with last version GAX/GAT installed).
Thanks your attention,
Otavio