The hardest part of working with the cloud is most often creating connections with on-premise systems. That's the key reason IBM acquired Cast Iron Systems in May, and it's why services provider ADP has chosen IBM Cast Iron to connect customers to its ADP Tax Services.

In a deal announced on Wednesday, ADP said it will offer customers of ADP Tax Services the option of using virtualized IBM Cast Iron software to integrate data from their on-premise systems to the service provider's cloud-based tax filing service.

ADP Tax Services cater to midsize companies with more than 250 employees that process payrolls in house -- using midrange ERP and accounting systems -- but that prefer to outsource complicated and every-changing tax filings.

ADP customers will download a small-footprint, virtual appliance version of IBM Cast Iron data integration software, running on VMWare or Xen virtual machines. The deployment will include prepackaged templates for common integration patterns between midrange ERP systems and ADP's cloud services.

"We can combine this software with support services so our customers don't have to be involved in data integration activities other than having the virtual software installed on their site," said Lori Schreiber, general manager and a vice president at ADP Tax and Financial Services.

ADP currently has about 1,300 Tax Service customers, but the vendor hopes it can grow that number by simplifying data integration. Customers currently use custom code or conventional ETL software -- an approach that typically takes 18 to 21 weeks to set up, according to ADP. End-to-end integration between ERP systems and ADP's cloud-based services should take less than 12 weeks using the new IBM Cast Iron-based offering, Schreiber said.

Once installed, the particulars of data integration can be remotely revised to adapt to new tax reporting requirements. As an example, the New-Hire Act implemented as part of the TARP program required changes in tax reporting and, thus, changes in integrations to ADP Tax Services.

"Federal, state and local tax laws change quickly, and this approach will enable ADP to quickly change templates so customer reporting changes on a real-time basis," said Ken Comee, president and CEO of IBM Cast Iron.

Once installed, the virtual appliance provided by ADP can be used for other integration tasks, Comee said. Additional ADP services as well as enterprise applications, like CRM and call center systems, are among the possibilities. Those end points could be on premises or in the cloud. Cast Iron has longstanding partnerships with Salesforce.com and other software-as-a-service providers, and built its business on on-premise-to-cloud integration.

The IBM Cast Iron data integration software is available immediately through ADP, and the company reports it has several customers already using the software. Costs were not disclosed.