Embedding HTML in Gridview HeaderText

[=?Utf-8?B?UGF1bA==?=]

I am trying to embed HTML in a gridview's HeaderText field.

Something like this:
<asp:BoundFie ld DataField="rfq_ 4567_count"
HeaderText="RFQ s<br>(4-5-6-7)" SortExpression= "rfq_4567_count "
HtmlEncode="tru e">
<ItemStyle HorizontalAlign ="Center" />
<HeaderStyle HorizontalAlign ="Center" />
</asp:BoundField>

But the HeaderText won't give me a HTML <brlinefeed.

Can this be done?