Filippo,
Unfortunately user's query string parameters are not passed to the application by GoToApplication.aspx. It's definitely a good idea, and we wish we thought about it before you did. We have logged it as a desirable feature and will implement it in the next release.
To work around the issue, you would have to use static port number. It's not ideal as port could be taken, but it's a perfectly workable approach until we add the feature in the next release.
Best regards,
UltiDev Team.
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