The solution is to pass the replacement to the ASP page through the link, and then letting the ASP environment substitute the value itself, e.g.

[Websydian page with link to ASP:]
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<form action="/myAspAPP/mypage.asp" method="POST">
<input type="hidden" name="myWebsydianField" value="/(AajA)">
<input type="submit" name="myCallASP" value="Call ASP page">
</form>
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[ASP page:]
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<p>This is the value of myWebsydianField: <% response.write(request.form("myWebsydianField")) %>. </p>
<%
' Store the field value for use later in the page
dim myWebsydianField
myWebsydianField = request.form("myWebsydianField")
%>
<p>This is still the value of the field: <% response.write(myWebsydianField) %>.</p>
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