Ok I have some info. Discuss *is* designed to store the createdon date, that's clear now. In the Discuss user page in the manager there is a place for createdon date (2nd of 3 tabs).
Second, I just found an interesting form in the rtfm, under the "discuss register controller"
http://rtfm.modx.com/extras/revo/discuss/discuss.controllers/discuss.controllers.register
I *think* this will provide the proper functionality for createdon, don't know what else it will help with. It is the standard register form for Discuss, without a doubt.
[[!Register?
&submitVar=`dis-register-btn`
&activationResourceId=`[[*id]]`
&activationEmailTpl=`disActivationEmailTpl`
&activationEmailSubject=`Thanks for Registering!`
&usergroups=`Forum New Member`
]]
<form class="dis-form dis-register" action="[[~[[*id]]]]register" method="post">
<h2>[[%discuss.register? &namespace=`discuss` &topic=`web`]]</h2>
<span class="error">[[+error.spam_empty]]</span>
<input type="hidden" name="spam_empty" value="" />
<label for="dis-register-username">[[%discuss.username]]:
<span class="error">[[+error.username]]</span>
</label>
<input type="text" name="username" id="dis-register-username" value="[[+username]]" />
<label for="dis-register-password">[[%discuss.password]]:
<span class="error">[[+error.password]]</span>
</label>
<input type="password" name="password" id="dis-register-password" value="[[+password]]" />
<label for="dis-register-password-confirm">[[%discuss.password_confirm]]:
<span class="error">[[+error.password_confirm]]</span>
</label>
<input type="password" name="password_confirm" id="dis-register-password-confirm" value="[[+password]]" />
<label for="dis-register-email">[[%discuss.email]]:
<span class="error">[[+error.email]]</span>
</label>
<input type="text" name="email" id="dis-register-email" value="[[+email]]" />
<label for="dis-register-show-email">[[%discuss.show_email]]:
<span class="error">[[+error.show_email]]</span>
</label>
<input type="checkbox" name="show_email" id="dis-register-show-email" value="1" [[+show_email]] />
<div style="padding-left: 140px; clear:both;">
[[+recaptcha_html]]
[[+error.recaptcha]]
</div>
<br class="clearfix" />
[[+discuss.login_error]]
<div class="dis-form-buttons">
<input type="submit" class="dis-action-btn" name="dis-register-btn" value="[[%discuss.register]]" />
</div>
</form>
This is very cool, I can't believe I came across this code.
I used the standard *Login* register user code to build by site, so this can explain a lot of my problems. I put the users in the right group (by number), but I don't register them as dis-register or anything like that.
But I don't think this will help me with extended fields, so I am going on to ClassExtender asap. That will be next.