Thank you for clarifying your requirement.
Unfortunately it is not possible to use a visual ActiveX control on a Formativ Form (ie. apart from those ActiveX controls already on Formativ’s component palette).
To make your OCX usable with a Formativ applet, I suggest you create another OCX/DLL which exposes a Form using this control in the way you require. Then your Formativ applet can create an instance of the Form OCX/DLL. Of course the Form should provide methods/properties for all input/output required by the applet.
For related information see also this post.
I hope this helps you.