diff --git a/library/HTTP_Adapter.ttcn b/library/HTTP_Adapter.ttcn
index b302a80..9ad1e4a 100644
--- a/library/HTTP_Adapter.ttcn
+++ b/library/HTTP_Adapter.ttcn
@@ -84,9 +84,16 @@
 	return f_overlay_HTTP_Header(hdr, custom_hdr);
 }
 
+function f_ts_body_or_empty(template (omit) charstring body) return template (value) charstring {
+	if (istemplatekind(body, "omit")) {
+		return "";
+	}
+	return body;
+}
+
 template (value) HTTPMessage ts_HTTP_Req(charstring url,
 					 charstring method := "GET",
-					 charstring body := "",
+					 template (omit) charstring body := omit,
 					 integer v_maj := 1, integer v_min := 1,
 					 charstring host,
 					 HeaderLines custom_hdr := { }) := {
@@ -96,8 +103,8 @@
 		uri := url,
 		version_major := v_maj,
 		version_minor := v_min,
-		header := valueof(f_ts_HTTP_Header(body, host, custom_hdr)),
-		body := body
+		header := f_ts_HTTP_Header(body, host, custom_hdr),
+		body := f_ts_body_or_empty(body)
 	}
 }
 
@@ -115,7 +122,7 @@
 
 template HTTPMessage tr_HTTP_Resp2xx := tr_HTTP_Resp((200..299));
 
-function f_http_tx_request(charstring url, charstring method := "GET", charstring body := "",
+function f_http_tx_request(charstring url, charstring method := "GET", template charstring body := omit,
 			   HeaderLines custom_hdr := { })
 runs on http_CT {
 	HTTP.send(ts_HTTP_Connect(g_http_host, g_http_port));
@@ -146,7 +153,7 @@
 
 /* run a HTTP request and return the response */
 function f_http_transact(charstring url, charstring method := "GET",
-			 charstring body := "", template HTTPMessage exp := tr_HTTP_Resp2xx,
+			 template (omit) charstring body := omit, template HTTPMessage exp := tr_HTTP_Resp2xx,
 			 float tout := 2.0, HeaderLines custom_hdr := { })
 runs on http_CT return HTTPMessage {
 	f_http_tx_request(url, method, body, custom_hdr);