integration clickatell bulk SMS with their api's in WHMCS

Project Description: Only apply if you have experience integration clickatell bulk SMS with their api's in WHMCS.com. I need the following developed to integrate with clickatell api's. A front end where people can register for a hosted solution to send bulk sms and singular sms. It should also support 2 way SMS. The spec is as follows and broken into the following modules: (Only registered and loged in users can send SMS!) Compose Message:- - Input mobile number - Input Title, first name, surname or custom - Message field - Characters set length to 160 characters but should have the ability to split messages - Scheduling of message for specific time with the following fields - Scheduled date and time for message - sms message type - delivery acknowledgements - Maximum credits - Message concatenation - Send message from Sender ID (if this is entered then reply to message should be disabled) - Activation of 2 way messages should be enabled here as well. Inbox for receiving messages - show unread, read and deleted messages - Export messages as txt or excel - Mark messages as deleted, read unread - Reply to messages - Advanced search features including the following - Date From: Date to: - Received from: - Records per Page: - Look for: - Search On: - Two-Way Numbers: Address Book - Search contacts, group, first name, last name and mobile number - Create new group, edit group and import. Settings - Edit contact information (related to user database of WHMCS) - Preferences, username, password currency, email alerts. - Routing profiles - Balance alerts - Manage sender id's (must have topped up balance to be allowed to change from number to sender name or other mobile number) Billing - Buy now - Pricing - Billing History - Transaction history - Automated Billing Message Reports - Refer to [login to view URL] (communicator) Payments will be made in stage payments for this piece of software... 25% up front, the rest in stages. It specifically has to be written in php 5.3, the latest version. Full testing of the product should be completed and the acompanying documentation to support testing included.