How to change the decimal separator from "." (dot) to "," (comma)

Hello,
I need to change the decimal separator from "." (dot) to "," (comma) to provide consistency with Polish number format. I cannot find any WebMaker/BizFlow settings for this.
I've tried to use normal textbox and currency textbox - in first case, there is possible to enter comma separator, but the error occurs in database operations

java.lang.NumberFormatException: For input string: "33,33"
at sun.misc.FloatingDecimal.readJavaFormatString(Unknown Source)
at java.lang.Double.parseDouble(Unknown Source)
at com.hyfinity.xengine.effectors.SQLStatement.setParamValueAndType(SQLStatement.java:356)
at com.hyfinity.xengine.effectors.SQLStatement.effect(SQLStatement.java:492)
at com.hyfinity.xengine.effectors.BaseEffector.effect(BaseEffector.java:195)
at com.hyfinity.xengine.core.Rule.fireWithoutContext(Rule.java:197)
at com.hyfinity.xengine.core.Rule.fire(Rule.java:146)
at com.hyfinity.xengine.core.RuleBase.processRules(RuleBase.java:289)
at com.hyfinity.xengine.core.RuleBase.forwardChain(RuleBase.java:215)
at com.hyfinity.xengine.XEngine.execute(XEngine.java:95)
at com.hyfinity.xagent.StandardXAgent.callXMLService(StandardXAgent.java:197)
at com.hyfinity.xagent.StandardXAgent.service(StandardXAgent.java:172)
at com.hyfinity.xplatform.XPlatform.service(XPlatform.java:429)
at com.hyfinity.xplatform.XPlatform.serviceRequest(XPlatform.java:387)
at com.hyfinity.xengine.effectors.Service.callService(Service.java:223)
at com.hyfinity.xengine.effectors.Service.effect(Service.java:179)
at com.hyfinity.xengine.effectors.BaseEffector.effect(BaseEffector.java:195)
at com.hyfinity.xengine.core.Rule.fireWithoutContext(Rule.java:197)
at com.hyfinity.xengine.core.Rule.fire(Rule.java:146)
at com.hyfinity.xengine.core.RuleBase.processRules(RuleBase.java:289)
at com.hyfinity.xengine.core.RuleBase.forwardChain(RuleBase.java:215)
at com.hyfinity.xengine.XEngine.execute(XEngine.java:95)
at com.hyfinity.xagent.StandardXAgent.callXMLService(StandardXAgent.java:197)
at com.hyfinity.xagent.StandardXAgent.service(StandardXAgent.java:172)
at com.hyfinity.xplatform.XPlatform.service(XPlatform.java:429)
at com.hyfinity.xgate.HTTP2Java.processAction(HTTP2Java.java:1065)
at com.hyfinity.xgate.HTTP2Java.doPost(HTTP2Java.java:633)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
at java.lang.Thread.run(Unknown Source)

When I use currency textbox there is a validation error for values with comma "this value must represent a valid number".
How can I change the decimal separator? Thank you.