hi R Pere,
usually the cmc logon screen would only appear when there is a logout / token expiration issue. i.e. the error doesn't really have anything to do with webelements as they only create a hyperlink and don't directly affect anything to do with sessions.
as a comparable flow, write down the opendocument url that is generated in mode 2 and then create a new hyperlink with that exact code. if you press that hyperlink on your report, this would basically be the same thing that the webelements functions produce, which is a report to report link. timeouts would be caused by other issues such as session settings in the cmc.
in order to affect charts and tables, this is still the same workflow as before where you have a parameter in your target report in the record selection filter, or a parameter which affects group sort, or a parameter which affects group selection. webelements create the controls and then the opendocument url which open the target report. so in your report design, you would start by creating those parameters which change your charts and tables by referencing the parameters in your record selection formula, and then in the report that contained the webelements controls, you would have those controls have the identical names as the parameters in your target report.
-jamie