private List<Header> getExpandedHeaders(final Request request) {

		final List<Header> headers = request.getHeaders();
		final List<Variable> contextVariables = workflow.getContext().getVariables();

		for (final Header header : headers) {
			final String newValue = VariableHelper.substituteVariables(header.getValue(), contextVariables);
			header.setValue(newValue);

			if (header.getName().equals("Content-Type") && header.getValue().startsWith("multipart/form-data")) {
				header.setValue("multipart/form-data;boundary=" + BOUNDARY);
			}

			println(" header:"  + header.getName() + " = " + header.getValue());
		}

		return headers;
	}