Variable scope - Code Snippet in Listpage Field

Hi,

I am struggling with displaying a gif image depending of a (text) field value.

1) I found that I can echo HTML code in a snippet (inserted in Page Editor into this field)
like

echo '<IMG alt="OFFLINE" src="images/offline.gif"  border=0>'; 

2) also in "BeforeProcessRowList" Event I can access/manipulate field contents using $data["your_field_name"]
however if I replace field content here, it is output as text (and not as HTML as under 1) )

? How can I access/(manipulate) field information in snippet . I tried using GetMasterRecord() to get a reference to $data,
but it did not work

Any suggestions?

Thx