Should the HTML returned be editable?  If not, perhaps using a data label would better fit your need:

https://help.k2.com/onlinehelp/k2smartforms/userguide/current/default.htm#sf_-_viewcontrols_-_data_label.html

Data Labels have a 'Literal' Property:

A Boolean value used to establish whether the text should be read as literal or plain text. In the following example:

<div style=”color:blue”>HTML Element</div>
If Literal = True, the result will be:
HTML Element
If Literal = False, the result will be:
<div style=”color:blue”>HTML Element</div>

The setting is disabled by default. If Literal is not selected, the control does not add any HTML elements to the text. This is useful when you want to render text and controls directly into a page without any additional markup