How to programmatically add Bizforms on custom web part

You have to add the control: <cms:BizForm ID="viewBiz" runat="server" IsLiveSite="true" />

Then you can set which form to use in SetUpControl() which is called in OnContentLoaded():

                viewBiz.FormName = FormName;
                viewBiz.SiteName = SiteContext.CurrentSiteName;
                viewBiz.UseColonBehindLabel = true;
                viewBiz.AlternativeFormFullName = AlternativeFormName;
                viewBiz.ValidationErrorMessage = "There was an error";

                // Set the live site context
                if (viewBiz != null)
                {
                    viewBiz.ControlContext.ContextName = CMS.ExtendedControls.ControlContext.LIVE_SITE;
                }

formname being a property I set on the webpart. Then in OnLoad you can add: viewBiz.OnAfterSave += viewBiz_OnAfterSave;

private void viewBiz_OnAfterSave(object sender, EventArgs e)
{
    if (TrackConversionName != String.Empty)
    {
        string siteName = SiteContext.CurrentSiteName;

        if (AnalyticsHelper.AnalyticsEnabled(siteName) && !AnalyticsHelper.IsIPExcluded(siteName, RequestContext.UserHostAddress))
        {
            HitLogProvider.LogConversions(SiteContext.CurrentSiteName, LocalizationContext.PreferredCultureCode, TrackConversionName, 0, ConversionValue);
        }
    }
}