Custom drop down not displayed

Suite and Optimus Suite 5
#1

I have a grid with filters at all 4 columns. Screenshot as below.

and this is the code

	Response.Write("<head>")

	strFilter = ",,#text_filter,#text_filter,#text_filter,#text_filter,,"

	Response.Write("<afterInit>")
		Response.Write("<call command='attachHeader'>")
		Response.Write("<param>")
			Response.Write(strFilter)
		Response.Write("</param>")
		Response.Write("</call>")
	Response.Write("</afterInit>")

	Response.write("<column id='column1' width='30' type='ch' align='center' sort='int'>")
		Response.write("")  
	Response.write("</column>")

	Response.write("<column id='column2' width='30' type='link' align='center' sort='int'>")
		Response.write("")  
	Response.write("</column>")

	Response.write("<column id='column3' width='200' type='ro' align='left' sort='str'>")
		Response.write(strColumnName1)  
	Response.write("</column>")

	Response.write("<column id='column4' width='500' type='ro' align='left' sort='str'>")
		Response.write(strColumnName2)  
	Response.write("</column>")

	Response.write("<column id='column5' width='150' type='ro' align='left' sort='str'>")
		Response.write(strColumnName3)  
	Response.write("</column>")
	
	Response.write("<column id='column6' width='150' type='ro' align='left' sort='str'>")
		Response.write(strColumnName4)  
	Response.write("</column>")
	Response.Write("</head>")

Now I want to make a custom drop down (select option) field in column 2 (Asset Brand Name). I modified the code as below

	Response.Write("<head>")

	strFilter = ",,#text_filter,<select><option value='0'>unchecked</option><option value='1'>checked</option></select>,#text_filter,#text_filter,,"

	Response.Write("<afterInit>")
		Response.Write("<call command='attachHeader'>")
		Response.Write("<param>")
			Response.Write(strFilter)
		Response.Write("</param>")
		Response.Write("</call>")
	Response.Write("</afterInit>")

However I’m getting only filter field at column 1, the rest of the filter seems to disappear. What went wrong here? Is my code correct? Somebody please help me.

Screenshot as below.

#2

It’s better to attach additional header before init:

 Response.Write("<beforeInit>")