How to set position of Participant's Signature With Rest API

Hi 

I can create participants and sing with them. 

But how can locate signature box at desired position?

	var rRequest = new RestSharp.RestRequest("api/rest/v6/agreements")
	{
		Method = RestSharp.Method.POST
	}
	.AddHeader("Accept", "application/json")
	.AddHeader("Content-Type", "application/json")
	.AddHeader("x-api-user", "email:" + pAPIUserEmail)      
	.AddHeader("Authorization", "Bearer " + integrationKey)
	.AddJsonBody(new
	{
		name = pDocumentCaption,

		fileInfos = new[] { new { transientDocumentId = transientDocumentId } },

		participantSetsInfo = new[] {
			new {
					memberInfos = new [] {
						new {
								email = pUserEmails[0]
							}
					},
					order = 1,
					role = "SIGNER",    
				},                       

			new {
					memberInfos = new [] {
						new {
								email = pUserEmails[1]
							}
					},
					order = 2,
					role = "SIGNER",   
				}                        

		},