is there a way of calling the process to calculate tax using the eTax engine but passing it data fro

Problem Description: we have a 3rd aprty web based product that needs to calcualte the tax on sales but then pass this information into Oracle OM then into Oracle AR. At the moment, we need to rely on the 3rd party product to calcualte the tax which is a very basic tax engine and will not meet all our needs. We want to use the eTax engine if possible to do this.
whilst we understand that this is a custom process we would like to try and  use Oracle functionality to feed data from a non-oracle product and then get the tax result out that we can pass back to the 3rd party product. The question is whether or not this can be done?