Thank you! Since "ResolveDynamicControls" is the correct tool to use, I must be doing something else wrong.
I simply take the text that contains the bizform, and assign it to the text field of a label control:
DisplayContent.Text = VariableContainingBizFormText;
Here are the exact HTML controls I use:
<asp:PlaceHolder runat="server" ID="plcHolder">
<asp:Label ID="DisplayContent" runat="server" Text=""></asp:Label>
Then I run ResolveDynamicControls on the parent control of the control that contains that "bizform text".
Maybe the label control is the wrong control to use for this? Or there's something else I need to 'turn on'?