Adobe Sign API: Show in ERP system actual status for Agreement.

Hi there!

I try to use Adobe Sign API.

The main goal is: show in ERP system actual status for Agreement.

I want to update Agreement status right after sign.

I do next steps:

1. Create Agreement with postSignOptions.redirectUrl=https://myserver/adobe_sign/post_sign

Result: new Agreement with agreementId like 3AAABLblqZhApmd08WhymSF9bL_Ol8HwhCa_ct-fSs-ZpeJinbBblI0RqnutaOyaoKQjletnN3Sl3Gllp_uFGz0vrrl_t_cUW

2. Get SigningUrls by agreementId

Result: signingUrl like https://secure.na1.echosign.com/public/apiesign?pid=CBFCIBAA3AAABLblqZhCbVBU6yOW7eSQqijLYninx0lRJ1niGNR1W4XlO5m7aMTShcfgOZT3ThwKH68ioyPg*

3. Open signingUrl in the browser

Result: browser redirects to url like https://secure.na1.echosign.com/public/esign?aid=CBFCIBAA3AAABLblqZhBOHxLgBBNOcPErbYm_uauX6pTqxCwzO2XnL21HN8YOLDRshhDl0jnTiSvo4EW4QSk*

4. Sing Agreement in the browser

Result: browser redirects to url https://myserver/adobe_sign/post_sign

5. ERP takes this and parses headers

Result: Referer contains url lik from step 3.

https://secure.na1.echosign.com/public/esign?aid=CBFCIBAA3AAABLblqZhBOHxLgBBNOcPErbYm_uauX6pTqxCwzO2XnL21HN8YOLDRshhDl0jnTiSvo4EW4QSk*

now ERP has some aid=CBFCIBAA3AAABLblqZhBOHxLgBBNOcPErbYm_uauX6pTqxCwzO2XnL21HN8YOLDRshhDl0jnTiSvo4EW4QSk

How does ERP can understand which Agreement it was (by aid=CBFCIBAA...)?

Or may be here is another approach to archieve main goal: "show in ERP system actual status for Agreement".